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Earth Magazine - May 2018

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WETLANDS REMEDIATE
NITROGEN POLLUTION
LA NIÑA TO BLAME
FOR WEST’S DRY WINTER
RECYCLING RAISES
LEAD LEVELS IN AFRICA
EARTH
Oman’s Outstanding
Ophiolites, Canyons
and Dunes
2E]ȶȉȦȁ
www.earthmagazine.org
The complete collection of Geotimes and
EARTHƒ‰ƒœ‹‡ϐ‹Ž‡•ǡͳͻͷ͸ǦʹͲͳ͹Ǥ
A lifetime of geoscience information and
Š‹•–‘”›‘‘‡ϐŽƒ•Š†”‹˜‡Ǩ
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PREMIER INTERNATIONAL CONFERENCE ON
ENERGY • MINERALS • WATER • THE EARTH
June 16-21, 2018
Vancouver Convention Centre
Vancouver, BC, Canada
WHY ON EARTH
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EARTH
2E]ȶȉȦȁ`ZSPȰȴRSȍ`[[[IEVXLQEKE^MRISVK
FEATURES
ȶȶ`+742+&7284+.18*7
Restored Wetlands Remediate
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8LIIEVP]ȶȉXLGIRXYV]MRZIRXMSRSJE
RMXVSKIRJM\EXMSRTVSGIWWVIZSPYXMSRM^IH
agriculture and made it possible to
feed the planet’s growing population.
But nitrogen runoff is polluting our
waterways and suffocating aquatic life.
Now, researchers looking for ways to
reverse that trend are turning farmland
into wetlands to filter nitrogen from
WXVIEQWERHVMZIVW`cNia Hurst
ȶȶ
ȶȁ`192,911.43
Colorado’s Natural “Lab” Offers Insights
Into Landslides Worldwide
.RWSYXL[IWXIVR(SPSVEHSEGIRXYVMIW
old landslide (first identified as such
MRȦȁȁȴF]ERMRJEQSYWTVSWTIGXSV
and purported cannibal) is offering
geologists an ideal laboratory to study
WPS[QSZMRKWPMHIW`cJane Palmer
ȶȁ
ȴȁ
VOICES
Ȱȏ GEOLOGIC COLUMN:
A WORLD WITHOUT MEASURE
The treaty establishing a global, uniform system of
QIEWYVIQIRX[EWWMKRIHSR2E]ȶȉȦȁȮȍ8SHE][ILSRSV
that achievement by celebrating World Metrology Day on
2E]cȶȉ`John Copeland
ȴȁ`87&:*1.3,*414,=
Northern Oman: Stunning Canyons,
Towering Dunes and the World’s
Largest Ophiolite
The small, politically stable sultanate
of Oman hosts the world’s biggest and
most intact ophiolite — a rare slice of
oceanic crust emplaced on land — as
well as stunning canyons, turquoise
swimming holes, lush palm oases,
'VSR^I&KIXSQFWIRHERKIVIHWIE
turtles and endless fields of sand
HYRIW`Lon Abbott and Terri Cook
ON THE COVER: Oman’s stunning sand dunes. Credit: Lon Abbott and Terri Cook
NEWS
Ȧȉ )49'1*).51&3.›&'1&2*)+47
COLORADO’S DRY WINTER
ȦȮ ORIGINS OF PLANT
PHOTOSYNTHESIS ILLUMINATED
ȦȦ WORLD’S LONGEST UNDERWATER CAVE FOUND
IN MEXICO
Ȧȁ RISING WATERS SINK SEAFLOORS
Ȧȶ WHATEVER HAPPENED TO THAGOMIZERS AND
OTHER TAIL WEAPONS?
Ȧȟ LIDAR PRESERVES RECORD OF DESTROYED
THEROPOD TRACKS
Ȧȴ
Ȧȴ UNPRECEDENTED
EXPLORATION OF
UNDERSEA VOLCANO
YIELDS SURPRISING
RESULTS
Ȧȟ
Ȧȟ +1.,-81*).34-&)'7.,-87&.3'4;
COLORED FEATHERS
Ȧȏ BATTERY RECYCLING
UNDERLIES ELEVATED
LEAD IN AFRICAN SOILS
ȶȉ
Ȧȍ HOT TROPICS DROVE
OUT ANCIENT REPTILES,
BUT THEY CAME BACK
ȦȰ RADIUM LEVELS
SUGGEST ARCTIC OCEAN
CHEMISTRY IS CHANGING
ȶȉ HOW BORNEO GOT ITS ELEPHANTS
Ȧȏ
ȶȉ NEW MAP OF TITAN SHOWS MOON’S
-.))*3c97+&(*
ȶȦ ICE (RE)CAP
DEPARTMENTS
ȏ FROM THE EDITOR
ȍȶ DOWN TO EARTH: With National Park Service
Senior Paleontologist
:MRGIRXcERXYGGM
Ȱ PERSPECTIVES
ȏȁ GEOMEDIA: BOOKS: Solar
Eclipses Past, Present
ERHc+YXYVI
ȍȉ WHERE ON EARTH?
ȍȦ (74*(8.43&5Y^^PI
ȍȰ BENCHMARKS:
2&=ȴȶȉȉȴ
New Hampshire’s Old Man
of the Mountain Falls
Ȱȉ CLASSIFIEDS: Career Opportunities
ON THE WEB AT www.earthmagazine.org
From the Editor
B
y age 2, my son could tell the
difference between a T. rex, a
Velociraptor, a Stegosaurus, an
Ankylosaurus and a Triceratops,
and he could pronounce them all. With
a collection of about 45 dinosaur figures
inherited from a cousin, he spends hours
imagining whole Jurassic and Cretaceous
worlds, lining up predators versus prey.
One of his favorite shows is PBS’ “Dino- Credit: House of Schaab Photography
saur Train,” hosted by paleontologist and EARTH contributing editor Scott
Sampson, aka “Dr. Scott, the paleontologist.” I’ve often wondered whether my
son’s early obsession with dinosaurs might translate into a career in paleontology.
Recently, I read a commentary in the Guardian by Mark Carnall, a paleontologist at the Oxford University Museum of Natural History in England, about the
childhood experiences that influenced him and many other professional paleontologists. Neither my husband nor I are paleontologists, but we encourage our
child’s obsessions. Regardless of his future career, as Carnall says, any childhood
“obsession” really leads to learning, growing and asking questions — which will
serve him well throughout life.
I suspect many EARTH readers have similar stories about a formative interest
or obsession that drew them to the geosciences. In our profile this month, Vincent
Santucci tells us how a walk through the fossil trails of Badlands National Park and
visits to the Carnegie Museum of Natural History in his hometown of Pittsburgh
inspired him to become a paleontologist. In our Geomedia review, solar physicist
Thomas Berger relates how inspiring it is to view a solar eclipse, an experience he
shared with his young daughter for the first time last year. And regular contributors
Terri Cook and Lon Abbott take us to Northern Oman, along with their children,
to visit something the authors have long dreamed of seeing: the world’s largest
ophiolite, a rare sliver of oceanic crust emplaced on land.
I hope you find inspiration in this month’s issue of EARTH, and pass it along
to the next generation.
EARTH
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[[[IEVXLQEKE^MRISVK
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Allyson K. Anderson Book
EXECUTIVE EDITOR
Christopher M. Keane
EDITOR
Megan Sever
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Mary Caperton Morton
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EARTH Editor
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TEKIȍ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Perspectives
8-*-.847=4+8-*Ȧȉȉ8-2*7.).&3
R
ichard Seager’s and Mingfang Ting’s research,
as summarized in “Dividing Line: The Past,
3UHVHQWDQG)XWXUHRIWKH൫൪൪WK0HULGLDQ” in the
January/February 2018 issue, eloquently demonstrates that the marked drop in population density
from east to west across the U.S.’s 100th meridian
is due to the change from grasslands to arid lands.
However, there is more to the story. Maps of
Native American territories prior to European
contact show a change of Native American tribes
to those more proficient at defending their lands
west of the meridian.
Credit: U.S. Geological Survey
This is especially true in Texas, which, by 1836, was the only place white
settlers had advanced far enough west to encounter the Plains Indians, according
to S.C. Gwynne’s excellent historic account, “Empire of the Summer Moon.”
According to Gwynne, the Comanches, the most powerful Native American tribe
in American history, had repulsed the mighty Spaniards and halted the advance
of the French. Beginning in 1836, they held off the colonizing Anglo-Americans
for 40 years. Comanches were far superior as horsemen to all who attempted
to conquer them and were masters of the Plains style of warfare.
Faced with such a formidable force, the advance of the frontier in the Southwest was not only stopped, it was rolled back, hundreds of miles in places, to
the relative safety of the forests. Later in the 19th century, similar, though less
drastic, scenarios played out when settlers faced tribes such as the Lakota Sioux
and Apaches across the 100th meridian. It must have been an easy choice for
pioneers to leap-frog the Plains to the gold fields opening up on the West Coast.
Climate and vegetation play the underlying role of controlling where and
how people live in America, but historically, warfare played the leading role in
halting westward migration of white settlers across the 100th meridian.
The AGI Foundation
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and young people —
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informed citizens of
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supporting the AGI
Foundation’s eforts.
Martin Ross
Geologist
Northeastern University
Boston, Mass.
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5411-4;143,;491)=498&=.3'*)
+47c(.*3(*$
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VIWXI\TIVMQIRXXSWXYH]XLILIEPXLSJEWXVSREYXWSRPSRKWTEGINSYVRI]W$-IVI
are the results:*
3S.GSYPHRƶXXEOIXLIFSVIHSQSVHMWGSQJSVXƾƾƾƾƾƾȍȍ
www.agifoundation.org
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=IW.[SYPHJSVXLIFIRIJMXSJWGMIRGIƾƾƾƾƾƾƾƾƾȦȉ
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News
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I
n January 2017, skiers at Wolf
Creek Ski Area in southern Colorado were enjoying a base snow
depth of more than 350 centimeters — enough snow to cover most rocks
and other obstacles. But this year, as of
mid-January, the runs were much sparser,
with the base barely clearing 100 centimeters. Powderhorn Resort in western
Colorado was so bereft of snow that
it had yet to open in mid-January — a
month behind its usual December opening. Statewide, the snowpack was slim
enough to worry not only skiers, but
also the state’s climatologists and water
resource managers, who held a Water
Availability Task Force (WATF) meeting
on Jan. 18 to discuss the state’s snowpack
and water outlook.
“Colorado had a very good winter
last year, in terms of snowpack, but we
started drying out over the summer and
started this winter at a moisture deficit,”
says Becky Bolinger, assistant state climatologist at the Colorado Climate Center
in Fort Collins. In late January, “none of
the basins in Colorado [were] anywhere
near normal snowpack,” she says. “Those
in the northern parts of the state [were]
faring the best, at around 80 percent of
normal, but as you go south and west,
the snowpack situation decreases into
drought conditions,” with the snowpack in some places as low as 37 percent
of normal.
Colorado gets most of its annual
moisture during the winter months in
the form of snow. The new water year
starts in October, with peak snowpack
occurring around April 1 before warmer
temperatures and longer days begin the
melt and runoff season in late spring. This
winter’s pattern — wetter in the north,
drier in the south — is typical of La Niña
years, says Klaus Wolter, a meteorologist with NOAA and the University of
Colorado Boulder who presented at the
WATF meeting.
La Niña is the cold phase of the El
Niño-Southern Oscillation (ENSO)
pattern, arising from cooler water
temperatures in the
equatorial Pacific Ocean,
while El Niño results
from warmer water
conditions in the same
region. In Colorado, La
Niña tends to produce
above average midwinter snowfall, especially in
the north, while El Niño
tends to produce wetter conditions in the fall
and spring and to favor
the southern mountains
over the north.
Last September,
Wolter’s (and other
seasonal forecast) models for the upcoming
water year predicted an
averagely wet La Niña
winter. But, he says, it
appears “my experimental outlook was too
optimistic, and most of Snowpack in some northern portions of the West was close to
the state has been much normal this winter, but in other areas, including as far north as
drier than we expected.” Oregon and southern Idaho, it was well below normal. Warm
In his WATF presenta- colors indicate below average snowpack.
tion, Wolter explained Credit: USDA Natural Resources Conservation Service
that the models failed to
account for the effects of what he calls the 1950s and in the early 2000s — both of
a “double-dip” La Niña, where La Niña which were anchored by triple La Niñas,”
conditions initially give way to neutral he says. “La Niña events often last longer
or El Niño conditions but then veer back than El Niño, and it seems like the longer
into La Niña. The 2016–17 winter saw a La Niña lasts, the drier it gets. We don’t
“decently wet” La Niña that transitioned fully understand why that is yet, but there
into a short-lived El Niño by the spring. are probably feedback loops at work.”
Part of the problem is that the SNOBut by fall 2017, conditions reverted
firmly back to La Niña.
TEL network that is used to monitor
This double-dip pattern has been snowpack conditions in real time was
observed three times in the past 11 years only established in the late 1970s and
(in 2007–09, 2010–12 and now 2016– early 1980s, so scientists only have 30
18) and 12 times in the past 110 years. to 40 years of data from which to draw.
Historically, the second year of La Niña “I’m hesitant to say this is directly related
tends to be drier than the first, but models to climate change because there’s a lot
don’t seem to take this delayed effect into we still don’t understand about how
account, Wolter says. The effect may be these systems work,” Wolter says. The
magnified even more in the event of a double-dip phenomenon is an area of
triple-dip La Niña, which has occurred ongoing research, with only a handful of
four times in the last 110 years. “We’ve had studies to date focusing on quantifying
two really major nationwide droughts — in the effect, he adds.
TEKIȦȉ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
News
In early February, global models predicted that the weak to moderate La Niña
was weakening going into the spring,
and would likely transition into neutral ENSO conditions in late spring and
early summer. “It’s not just El Niño or
La Niña that impacts weather patterns,”
Bolinger notes. “We also have to take into
consideration how the jet stream moves
storms over the region and how much
moisture is lost from storms before they
even reach us.”
“Every little bit helps, but at this
point it’s very unlikely we will make
up the deficit,” Bolinger says. “I will not
be surprised to see worsening drought
conditions [in Colorado] for the south
and west regions going into the spring.”
Making up for the anemic snowpack
will require more than 30 centimeters
of snow-water equivalent over the
next three months, a gain that has only
occurred three times in the last 37 years.
“Every now and then we get a lot of snow
late in the spring, but that’s much more
Andromeda brought down to size
8LI&RHVSQIHEKEPE\]SYVRIEVIWXQENSVKEPEGXMGRIMKLFSV[IMKLWȁȉȉ
billion times as much as the sun, meaning it’s on par with the Milky Way,
according to new research. Previous estimates suggested Andromeda
[IMKLIHEWQYGLEWȶȍXVMPPMSRWSPEVQEWWIWFYXEWXVSRSQIVWJSYRHXLEX
XLIKEPE\]GSRXEMRWJEVPIWWHEVOQEXXIVXLERXLSYKLX;LIXLIV&RHVSQIHE
and the Milky Way are really in the same weight class may still be debat
EFPIVIGIRXQEWWIWXMQEXIWJSVSYVS[RKEPE\]LEZIZEVMIHJVSQEFSYX
ȶȉȉFMPPMSRXSȦXVMPPMSRWSPEVQEWWIW
0EJPIIXEP2SRXLP]3SXMGIWSJXLI7S]EP&WXVSRSQMGEPSGMIX]/ERYEV]ȶȉȦȁ
common in El Niño years,” Wolter says.
“That kind of ‘Miracle May’ situation
isn’t going to save us this year.”
Other states in the West, such as Montana and Wyoming, have been faring
better than Colorado, but the dryness
trend seen in southern and western Colorado is also affecting Arizona, California,
Nevada, New Mexico, Utah and Oregon. As of Feb. 1, the snowpack in the
California Sierras was at just 27 percent
of normal. This trend was also generally underpredicted by seasonal forecast
models for the West, Wolter says. “So far
it seems like the jet stream is anchored
farther north,” he says. “Storms are hitting western Canada and the northern
U.S., but they’re not percolating south
[as much], and when they do, they aren’t
as strong as they have been in the past.”
This isn’t just a problem for skiers and ski
resorts: Since most states across the West
get their water from the snowpack, water
managers are worried about resources for
the rest of the year.
Mary Caperton Morton
World’s longest underwater cave
JSYRHMR2I\MGS
I
n January, scientists and underwater explorers working with the
Great Maya Aquifer (Gran Acuífero
Maya, or GAM) project discovered
the world’s longest flooded cave system,
which stretches 347 kilometers in Quintana Roo on Mexico’s Yucatán Peninsula.
After 10 months of intensive fieldwork, the team found a connection
between two of the largest flooded caverns in the world, called Sac Actun and
Dos Ojos, in the coastal town of Tulum,
which is famous for its Mayan ruins.
Before the discovery, the longest
underwater cave was 270-kilometer Ox
Bel Ha, located south of Tulum. Sac Actun
ranked second at 263 kilometers while
Dos Ojos was fourth at 83 kilometers.
With a connection between the latter two
established, and according to speleological convention under which the name
of the larger cave takes precedence, the
entire system is now known as Sac Actun
and is considered the longest underwater
cave in the world.
Finding the connection required hundreds of hours of treacherous diving and
mapping in the submerged labyrinth.
GAM explorers plan to search for connections between Sac Actun and three
other systems of nearby caves.
Part of GAM’s mission is to understand the history of the region’s ancient
Maya civilization and its relationship to
the aquifer system, as well as to protect
and conserve the aquifer as a valuable
natural resource.
The new cave is home to remains of
extinct animals, along with artifacts that
provide insight into North America’s
earliest settlers and the Maya civilization,
said Guillermo de Anda, GAM director
and an underwater archaeologist at Mexico’s National Institute of Anthropology
A connection between the Dos Ojos (seen
here) and Sac Actun caves near Tulum,
2I\MGS[EWVIGIRXP]HMWGSZIVIH8LIRI[P]
GSQFMRIHGEZIW]WXIQMWRS[XLIPSRKIWX
known underwater cave in the world.
Credit: ,YMPP³R5³VI^(('=3)ȶȉ
and History, in a statement. “This huge
cave represents the most important submerged archaeological site in the world.”
TEKIȦȦ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Bethany Augliere
News
;LEXIZIVLETTIRIHXSXLEKSQM^IVWERHSXLIV
tail weapons?
S
tegosaurus wielded a spiked tail
— dubbed a “thagomizer” by cartoonist Gary Larson and informally
adopted by paleontologists — which
the herbivorous dinosaur likely used for
defense against hungry predators. Other
extinct animals also sported foe-clobbering tail weapons: Ankylosaurus had a tail
club, as did extinct mammals like the glyptodonts, giant armadillo-like animals that
once roamed the Americas. Today, though,
thagomizers and bony tail clubs are things
of the past. In a new study, paleontologists
have found that extinct animals with such
weapons all shared a now-antiquated set of
traits: They were large, herbivorous, and
had body armor and a stiff torso.
This cocktail of characteristics does
not exist in any living animal, says Victoria Arbour, a vertebrate paleontologist at
the Royal Ontario Museum in Toronto,
Canada, who led the new research, published in Proceedings of the Royal Society
B. Other weapons, like those that adorn
the heads of many ancient and living animals, appear to be commonplace, while
Global sea-level rise
accelerating
A new analysis of satellite altim
IXV] HEXE GSPPIGXIH WMRGI Ȧȟȟȴ
indicates that the global rate of
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TIV ]IEV SZIV XLI TEWX ȶȍ ]IEVW
MW EGGIPIVEXMRK F] VSYKLP] ȉȉȁ
millimeters per year. If this accel
eration trend continues, the rate
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PIZIP[MPPFIEFSYXȰȉGIRXMQIXIVW
higher than today, roughly double
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per year.
Nerem et al., Proceedings of the National
&GEHIQ]SJGMIRGIW+IFVYEV]ȶȉȦȁ
tail weapons are rare. “We
wanted to dig into why that
might be,” Arbour says.
Teaming with Lindsay
Zanno, a vertebrate paleontologist at the North Carolina
Museum of Natural Sciences
and co-author of the new study,
Arbour studied the evolution of
tail weapons by examining 286
diverse taxa, some of which had
weaponized tails and some of
which did not, including tur- 3I[VIWIEVGLJMRHWXLEXI\XMRGXXEMP[IETSR[MIPHMRK
tles, bison and long-necked, animals — such as the dueling ankylosaurs illustrated
long-tailed sauropod dinosaurs, here — all shared a set of traits, including large body
among others. “Using phyloge- WM^ILIVFMZSV]ERHFSR]FSH]EVQSVXLEXRSQSHIVR
netic comparative methods lets animals possess.
us test for statistical significance Credit: Jack Mayer Wood
in trait correlations” among
taxa, Arbour says. From the researchers’ that along with body armor, a stiff body
analysis, large body size and herbivory — which would have helped animals brace
correlated most strongly with possession themselves against the forces generated
of tail weaponry, shedding light on the by swinging their tails — may have been
absence of such weapons in smaller her- a necessary pre-adaptation.
bivores. “Several small lizards today [like
Tail weapons seem to have disappeared
the spiny-tailed lizard] use spiky tails as about 10,000 years ago with the extinction
defensive weapons, but elaborate bony of the glyptodonts. Large modern herbitails were more likely to evolve in large vores may lack tail weapons for defense
herbivores,” she says. Bony body armor in part because the selective pressure that
is another trait that co-occurred with tail led to the weapons’ evolution in the older
weapons in Arbour and Zanno’s analysis. taxa eventually subsided as other defensive
This is the first research to test ques- strategies emerged, like the ability to outtions about the evolution of tail weapons run predators or traveling in herds.
in a quantitative way, says Susie MaidOne remaining mystery is why tail
ment, a vertebrate paleontologist at the weapons did not emerge in carnivores.
Natural History Museum in London who While Arbour and Zanno did not directly
was not involved in the work. “The study address carnivores in their research,
doesn’t state that all of the requirements Arbour says that carnivores may not have
the authors identify have to be met for bony tail weapons because they already
weaponry to evolve; it simply shows have enough armament in the form of
correlations between specific traits and sharp teeth or claws, or other adaptations.
weaponry,” Maidment says. However, she Even so, she points out that some modsays, body armor was likely a necessary ern carnivores do in fact use their tails
precursor to the evolution of tail weapons. as weapons: “Monitor lizards will whip
In some animals, this armor allowed for “a their tails to deter predators, even though
more active form of defense at the end of they are predators themselves,” she says.
the tail.” The results suggest that animals “There’s a lot to learn about this unusual
that evolved bony tail weaponry had to behavior in living animals.”
be “pre-adapted to do so,” she says, noting
Lucas Joel
TEKIȦȶ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
News
9RTVIGIHIRXIHI\TPSVEXMSRSJYRHIVWIEZSPGERS]MIPHW
surprising results
U
nderwater volcanic eruptions happen every day,
but because of the vastness of the ocean and the
great depth of water blocking the view,
catching an active eruption is a game
of chance. In fact, the largest-known
underwater eruption of the past century
was something of a fluke discovery. In
July 2012, an airline passenger spotted
a huge pumice raft floating in the South
Pacific during a flight to Auckland, New
Zealand. Upon landing, she alerted
researchers, and scientists confirmed
the 400-square-kilometer pumice raft
near the Havre Seamount using NASA
satellite imagery.
“It was pretty clear that [the pumice]
originated from Havre because the satellite imagery was showing a plume coming
from a point source and extending out
from that point,” says Rebecca Carey, a
volcanologist at the University of Tasmania in Australia and lead author of a
new study in Science Advances detailing findings about the 2012 eruption.
Havre, discovered in 2002, is a submarine
volcano located about 1,000 kilometers
north-northeast of the North Island of
New Zealand.
Three years after the discovery of the
pumice raft, Carey and other researchers set sail for Havre to document the
eruption. The scientists launched an
autonomous underwater vehicle and
remotely operated vehicles to observe
and sample the ocean floor around Havre.
“We work on terrestrial volcanoes and
so we had expectations about what we
would see on the seafloor,” Carey says.
“Basically, from the first observation
on the seafloor, we had to throw those
[assumptions] out the window.”
Observing Havre underwater revealed
the complexity of the eruption, Carey
says. The team found 14 volcanic vents,
destabilized walls of the volcano, and a
strange deposit of especially large pumice
clasts up to 9 meters in diameter.
Seeing the topography allowed the
team to document dispersal patterns and
determine which vent was responsible
for producing what lava flows, including
the clasts — a feature not seen on land
volcanoes. “It seems that voluminous
deposits filled with these [large] pumice clasts are diagnostic of a submarine
setting,” Carey says. During eruptions
from volcanoes on land, magma rising
to the surface can accelerate quickly with
decreasing pressure, bursting into the air
and fragmenting into small pieces that
average about 2 millimeters across, she
explains. In submarine environments,
especially in deepwater, Carey says, “you
have the weight of the overlying water
column, so the magma ascends much
more slowly” and doesn’t fragment into
tiny pieces.
Another surprising realization for the
team, Carey says, was that the volcanic deposits on the seafloor probably
don’t tell the whole eruption story. Using
the satellite-based record of the pumice
raft and the detailed survey of the ocean
deposits, the scientists calculated that
about 80 percent of the pumice from
Havre made it up into the raft and was
carried away by ocean currents, much
of it eventually ending up on Australian
beaches in the years after the eruption.
Indeed, fine material can escape the scene
quickly on currents, or even through the
atmosphere in shallow eruptions. “Having a quick-response cruise to observe
the seafloor and deposits rapidly, before
they’re altered by currents, is incredibly valuable,” says Nick Deardorff, a
volcanologist at Indiana University of
Pennsylvania who was not involved in
the study.
This research showed that the “geologic record on the volcano edifice is
really biased” because most of the material
is lost to the ocean, Carey says, adding
that it’s something to keep in mind when
piecing together the eruption history of
older volcanic deposits.
1EZEJVSQXLIȶȉȦȶIVYTXMSRSJXLI-EZVI
underwater volcano is shown in shades of
VIHMRXLMWLMKLVIWSPYXMSRQSHIP
Credit: University of Tasmania/Woods Hole
Oceanographic Institution
The Havre research also illuminated
another important tool in studying
ancient deposits, Deardorff says: those
large pumice clasts can provide another
way to tell an eruption above sea level
from a submarine eruption. Features like
these, or others, like the better-known
pillow basalts, that only occur underwater
or in contact with ice, can help volcanologists determine the type of eruption in
ancient rocks, he adds.
Carey notes that researching active
submarine volcanoes can also spur unexpected interdisciplinary discoveries.
During the research cruise, for example,
the team observed what an underwater
eruption can do to local biological communities. “We got to the volcano three
years after the eruption and virtually
nothing had recolonized — it’s like a
moonscape,” Carey says. “Havre provides
an end-member example of the devastation” that submarine volcanoes can inflict
on seafloor environments, she says.
As a result, the eruption has caught
the attention of biologists and hydrothermal ecologists. Carey says another
voyage back to Havre is being planned
for 2020 to study recolonization and
ecosystem recovery in submarine volcanic environments.
TEKIȦȴ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Sarah Derouin
News
Battery recycling underlies elevated lead in African soils
O
f all the recycling industries
in the world, lead-acid battery recycling is one of the
most profitable — and one
of the most toxic. In the U.S., regulations
on the industry have dramatically reduced
lead exposure and pollution at battery
recycling plants. But in Africa, where the
industry is growing and largely unregulated, lead levels are skyrocketing. A new
study in Environmental Research looking
at environmental lead levels in seven
African countries is shining a spotlight
on the ongoing public health crisis.
Last year, the medical journal The
Lancet published a report on pollution
and health that showed that pollution
contributes to more deaths worldwide
than anything else. Lead poisoning alone
is estimated to kill between 1.5 million
and 2 million people worldwide each
year, many of them children who are
more susceptible to its insidious neurological effects.
Ribbon of North America
found in Australia
Australian researchers have found
rocks in northern Queensland
that match a similar unit in Can
ada, suggesting that part of
northern Australia rifted from
North America during the late
5EPISTVSXIVS^SMG ERH XLI IEVP]
2IWSTVSXIVS^SMG 5VIZMSYWP] XLI
rocks were thought to have been
TEVXSJ&YWXVEPMEF]ȦȮFMPPMSR]IEVW
ago. However, the new research,
FEWIHSRHIXVMXEP^MVGSREKIWERH
paleocurrent data, suggests that a
ribbon of crust rifted from western
1EYVIRXME TVSXS3SVXL &QIVMGE
VSYKLP]ȦȰȁFMPPMSR]IEVWEKSERH
then collided with and accreted
XS &YWXVEPME F] ȦȰ FMPPMSR ]IEVW
ago during the formation of the
supercontinent Nuna.
3SVHWZERIXEP,ISPSK]/ERYEV]ȶȉȦȁ
1IEHEGMH FEXXIVMIW ƴ YWIH XS TS[IV
motor vehicles and cellphone towers, and
for power storage at wind and solar farms
— are one of the most recyclable products,
FYXXLI]EVIEPWSLMKLP]XS\MG
Credit: FEWIPEGXMSRRIX[SVO(('=3)ȶȉ
“If you look at the global lead poisoning
epidemic, the lead car battery recycling
industry is one of the main culprits,” says
study lead author Perry Gottesfeld, executive director of Occupational Knowledge
International, a nonprofit focused on
public health issues related to industrial
pollution. Car batteries, which are typically
replaced every few years, account for the
vast majority of the lead-acid batteries
recycled; cellphone towers, solar and wind
power farms, and computer server farms
also rely on rechargeable lead-acid batteries. “Lead car batteries are one of the most
recyclable products in the world. You can
make a whole new battery from recycling
an old one. It’s quite economically profitable,” says Gottesfeld.
But few low- and middle-income
countries have regulations in place to
enforce pollution and exposure controls.
“In the U.S., recycling plants have made
major improvements in recent decades
to meet the emissions standards imposed
by the Clean Air Act,” Gottesfeld says.
These improvements include sealing
plants to reduce emissions, monitoring
ambient air quality and tracking blood
lead levels in workers. Steps as simple as
showering before going home can greatly
reduce lead transport by plant workers
into their homes.
“We have the technology to make this
a relatively clean industry. It’s even economically feasible, but in many places the
industry just isn’t regulated,” Gottesfeld
says. In formal recycling plants in Africa,
he says, pollution controls are “lacking in
all ways, in terms of occupational exposure to workers and their families, and in
the emissions from these plants.” A lack
of automation in some plants means that
workers spend their days dismantling old
batteries with axes to remove the lead.
There are also “people melting down lead
batteries right outside their homes to sell
the scrap.” In total, Africa produces more
than 800,000 tons of lead from recycled
batteries each year.
Few studies have documented lead
levels around battery recycling plants
in Africa. Gottesfeld and his colleagues
collected soil samples from bare ground
inside 15 recycling plants in Cameroon,
Ghana, Kenya, Mozambique, Nigeria,
Tanzania and Tunisia, as well as within
a half-kilometer radius outside the
plants. They found lead levels as high as
140,000 milligrams per kilogram (mg/
kg), with averages of about 57,700 mg/
kg inside the plants and 2,600 mg/kg
outside, far surpassing the U.S. Environmental Protection Agency’s soil hazard
level of 1,200 mg/kg (or 400 mg/kg in
“children’s play areas”).
Blood lead levels of workers in African battery recycling plants, and their
families, have also not been documented
in detail, in part because many African
countries lack sufficient laboratory facilities to process the samples, Gottesfeld
says. The U.S. Centers for Disease Control and Prevention (CDC) estimates that
blood lead levels among children generally rise by 3 to 7 micrograms per deciliter
DŽJGO IRU HDFK LQFUHDVH RI PJ
kg of lead in soil. Both the CDC and the
World Health Organization recommend
action be taken when blood lead levels are
over 10 μg/dl in adults or 5 μg/dl in children, although no amount of lead in the
blood is considered safe, Gottesfeld says.
“In low-income countries, there is very
little awareness about the toxicity of lead
at all levels,” says Richard Fuller, an engineer with Pure Earth, an international
TEKIȦȏ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
News
nonprofit that identifies and remediates
polluted sites around the world. “When
we measure blood lead in these places, it’s
not unusual to see levels over 40 or 50 [μg/
dl],” he says, which is high enough to cause
convulsions, permanent brain damage,
kidney failure, heart failure and death.
“Studies like this are important for
highlighting the global burden of lead
poisoning,” says Fuller, who was not
involved in the work. “Lead poisoning
affects on the order of half a billion people worldwide, but there is very little
awareness or funding to solve this issue.”
However, regulations on recycling plants
have helped where they’ve been enacted,
such as in Vietnam, where “we saw average blood lead levels of 45 [μg/dl] go
down to 8 within about a year.” Solving
the issue in the seven African countries
Oceans starting to heat up the land
Most of the heat associated with rising global temperatures has been stored
MRXLISGIERWFYXWSQISJXLEXLIEXMWRS[FIMRKVIIQMXXIHERHGSRXVMF
uting to warming over land. For the first time, researchers have quantified
EƸNYQTƹMREZIVEKIKPSFEPXIQTIVEXYVIWSZIVPERHMRȶȉȦȏȶȉȦȍERHȶȉȦȰ
ƴ XLI[EVQIWX GSRWIGYXMZI]IEVW WMRGI VIGSVHOIITMRK FIKER MR Ȧȁȁȉ
8LI]GSVVIPEXIHXLINYQTXSI\GIWWLIEXGSQMRKJVSQXLISGIERWQYGL
SJMXFIMRKVIPIEWIHJVSQXLI5EGMJMG4GIERHYVMRKXLIȶȉȦȍƳȶȉȦȰ*P3M¼S
=MRIXEP,ISTL]WMGEP7IWIEVGL1IXXIVW/ERYEV]ȶȉȦȁ
highlighted in the new study will require
“a country by country and city by city
approach to force, ask or cajole the formal plants to improve their facilities,
and to educate people about the dangers
of informal recycling practices,” he says.
Gottesfeld and his colleagues plan to
conduct more environmental toxicity
studies around recycling plants and also
to measure blood lead levels in workers, their families and communities
near recycling plants. “It’s important to
remember this isn’t some marginal industry,” Gottesfeld says. “It’s an industry that
operates profitably and at a large scale.”
Mary Caperton Morton
Hot tropics drove out ancient reptiles,
but they came back
A
bout 252 million years ago,
massive volcanic eruptions in
what is now Siberia rapidly
warmed Earth, resulting in
the end-Permian mass extinction that
saw most terrestrial and marine species
die off. It’s been thought that surviving
reptiles and fish fled the hot tropics and
didn’t return for millions of years. But
according to new research, the tropical
evacuation may not have lasted so long
after all.
“We confirmed that there was a
flight from the equatorial belt,” but it
was shorter and less pronounced than
previously thought, says Mike Benton,
a paleontologist from the University of
Bristol in England and co-author of a new
study in Proceedings of the Royal Society
B: Biological Sciences.
During the end-Permian extinction,
ocean temperatures worldwide increased
10 to 15 degrees Celsius, rising to above
40 degrees in the tropics. Air temperatures rose dramatically as well. As a result,
two-thirds of the four-legged land vertebrates, or tetrapods, which were all
reptiles, went extinct. Previous studies
suggested the remaining reptiles avoided
the tropics for the entire 5-million-year
duration of the Early Triassic.
Benton and his colleagues wanted to
figure out if this absence was real or
an artifact of gaps in the fossil record.
Studies often focus on skeletal remains
to study vertebrate evolution, but ignore
geographically widespread footprint data,
Benton says. Alongside existing skeletal
fossils from the time period, most of
which have been found in Russia and
South Africa, the team analyzed fossil
footprints from Western Europe, North
America and Asia across a wide range of
latitudes from the equator to the poles.
“We didn’t have to identify which species produced each footprint, simply that
some backboned animal had produced a
footprint at that spot and at that time,”
Benton says.
They found that many land reptiles
did escape the tropical heat and move
poleward by 10 to 15 degrees latitude,
but the team’s footprint data suggests
that some tetrapods remained at low
Terrestrial reptiles vacated the tropics
(orange and yellow belts) following the
IRH5IVQMERQEWWI\XMRGXMSRȶȍȶQMPPMSR
years ago.
Credit: MUSE Archive
latitudes through the aftermath of the
extinction. Additionally, the initial flight
from the equator was less than 5 million
years, Benton says, as indicated by skeletal
records that show a return of some tetrapods to the tropics during the Olenekian
Age (251.2 million to 247.2 million years
ago) of the Early Triassic. However, the
Early Triassic had at least three sharp episodes of global warming, and it remains
to be seen if life fled the equator multiple
times, he says.
TEKIȦȍ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Bethany Augliere
News
Radium levels suggest Arctic Ocean chemistry is changing
R
ising temperatures have
already caused changes in
the Arctic environment,
like diminishing sea ice
and thawing permafrost. Now, it
appears that sea-ice loss could be
throwing Arctic Ocean chemistry out of whack.
In a new study in Science Advances, researchers
suggest that, increasingly,
materials like nutrients
and trace metals are mixing into the Arctic Ocean
from continental shelf sediments. This could disrupt
the Arctic food web, affecting
organisms from tiny phytoplankton up to polar bears, says
lead author Lauren Kipp, a chemical oceanographer at Woods Hole
Oceanographic Institution in Massachusetts. “Changes are already happening in
this region,” Kipp says. “It’s important
for us to understand and monitor how
[they] are happening, so that we can
predict how the Arctic will change in
the future.”
In 2015, working aboard the U.S.
Coast Guard icebreaker Healy, Kipp and
her team sampled Arctic surface waters
at 69 sites from the Chukchi Shelf to the
North Pole; they also sampled vertical
profiles of the water column at 20 sites.
The scientists then measured concentrations of radium in each sample. Radium
is produced naturally by the decay of thorium isotopes, which occurs in rocks and
soils. Unlike thorium, however, radium
dissolves in water. “It’s added to the ocean
when seawater encounters the coastline
or continental shelf sediment,” Kipp says.
So “the radium acts as a tracer of shelf
inputs to the ocean.”
The researchers found surprisingly
elevated radium levels in parts of the Arctic, including near the North Pole where
concentrations had doubled compared
to measurements taken in a 2007 study,
as well as near the Chukchi Shelf. “We
expected [radium concentrations] to be
.RȶȉȦȍVIWIEVGLIVWQIEWYVIHVEHMYQMRXLI&VGXMG
Ocean from the Chukchi Shelf (where the voyage
started) to the North Pole. Elevated radium
levels (shown in bright yellow along the
cruise route) were found near the
North Pole, possibly as a result of
transport from the East Siberian
Arctic Shelf.
Credit: Natalie Renier, Woods Hole
Oceanographic Institution
the same,” Kipp says, because sources
and sinks of nutrients and chemicals
in the ocean are typically balanced and
consistent over time — remaining stable
for up to millennia for certain elements
like sodium and chloride. For radium, in
particular, the researchers didn’t expect
to see an increase over just a decade. The
radium levels Kipp and her team found
were also 10 times higher than they are
in the Atlantic Ocean.
It’s not clear why radium concentrations have doubled, Kipp says, but
she and her co-authors suspect that
shrinking sea-ice coverage in the Russian Arctic has something to do with it.
As ice retreats from the East Siberian
Arctic Shelf — the largest continental
shelf on Earth — surface waters there
are more exposed to wind, which, in
turn, can lead to more mixing in the
water column over that shelf, she says.
Once shelf sediments are mixed into
the water, they can travel from Russia,
via the Transpolar Drift Current, to the
central Arctic, where increased radium
levels were detected. “These shelves
are really shallow,” Kipp
says. “On average, they’re
about 50 meters deep, so
it doesn’t take much to
increase the communication
between the sediment and the
water column.”
Radium in the Arctic Ocean
may have other sources as well,
like meltwater from thawing permafrost or rivers carrying eroded sediment
from the land surface, but Kipp’s team
calculated that those contributions are
small compared to shelf sediments. “Right
now, the best evidence [of high radium
in the Arctic Ocean] is consistent with
what she [Kipp] describes in her paper,”
says Robert Anderson, a chemical oceanographer from Columbia University’s
Lamont-Doherty Earth Observatory,
who was not involved in the new study.
Kipp says she wants to figure out
the rate at which the radium concentrations in the Arctic are increasing and
to confirm where exactly the radium
is coming from. “Is this a widespread
phenomenon, or happening in just one
place?” she asks.
“There’s a real need for measurements
on the Siberian shelf,” Anderson notes,
because it’s the widest shelf and the biggest source of sediment-derived inputs to
the Arctic Ocean. But access to Russian
territorial waters has been historically
difficult. He says he hopes Russian scientists will take the lead on this work,
because collaboration is “going to be key
to understanding the changes going on
in the Arctic.”
TEKIȦȰ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Bethany Augliere
News
Origins of plant photosynthesis illuminated
P
hotosynthesis, the process by
which plants harness sunlight
to make their food, is a defining feature of plants and an
important evolutionary development.
But when photosynthesis evolved in
ancient plant ancestors is not clear.
The Precambrian fossil red alga Bangiomorpha pubescens, discovered in the
Canadian Arctic in 1990 by University
of Cambridge paleobiologist Nicholas
Butterfield, displays evidence of traits
that suggest it photosynthesized the
way plants do, but the exact age of
the fossil was also unknown. In a new
study, researchers report an age for the
alga of about 1.047 billion years, making it the oldest-known direct ancestor
of plants.
The alga is also now the oldest-known
eukaryote — or complex organism — that
still has descendants alive today. “It stands
out as simply the most important fossil
for our understanding of early eukaryotic evolution,” says Timothy Gibson,
a doctoral student at McGill University in Canada who led the new study
in Geology.
It was long thought that B. pubescens
could be as old as 1.2 billion years, Gibson says, but this age came with a lot
of uncertainty. “It was only constrained
to a 500-million-year window between
1.2 billion and 700 million years ago,”
he says, which prevented researchers
from saying anything definitive about
the fossil’s significance as an ancestral
organism. “We show that the fossil is
about 200 million years older than the
next [oldest] fossil that you’d compare it
to,” which is a green alga, Gibson notes.
On Baffin Island in the Canadian
Arctic, Gibson and his colleagues took
samples of black shales from rock layers
above and below where B. pubescens fossils
occur. The team then dated the shales
using rhenium-osmium radiometric dating, which is only possible in rocks like
black shales with high levels of organic
matter, Gibson explains, because the
organic matter concentrates otherwise
minute amounts of
rhenium and osmium.
The age of the alga
means that eukaryotes
began diversifying
much earlier than
previously thought,
during a stretch of time
from about 1.8 billion
to 0.8 billion years ago
colloquially known as
the “boring billion”
because not much is
thought to have happened in terms of the
evolution of life. “This
study throws a wrench
into the mix,” Gibson says, and makes the
boring billion seem a little livelier.
With a precise age for B. pubescens,
the team was then better able to estimate
when photosynthesis likely emerged in
plant ancestors. In plants, photosynthesis
happens in organelles called chloroplasts,
which eukaryotes originally acquired
through a process called “primary plastid
endosymbiosis,” Gibson explains. “This
occurred when an ancient eukaryote
engulfed a photosynthetic bacterium” and
assimilated its photosynthetic machinery
into its genome.
To determine when this endosymbiosis and assimilation occurred, the team
employed a molecular clock analysis,
which estimates when certain evolutionary events happened based on the
relatively constant rate of DNA evolution, using the new age for B. pubescens to
help calibrate their molecular clock. The
researchers reported that the endosymbiosis occurred about 1.25 billion years
ago, likely in an unknown organism even
older than B. pubescens.
This date still comes with uncertainty,
however, because “molecular clock analyses on this timescale are notoriously
unstable,” says Butterfield, who was not
involved in the new study. Other such
analyses looking at when eukaryotes
acquired chloroplasts provide much older
dates, he says.
Bangiomorpha pubescens is a
fossil red alga that’s now the
SPHIWXORS[RHMVIGXERGIWXSV
of plants.
Credit: Nicholas Butterfield
While the new fossil age
reveals the oldest-known
eukaryotic ancestor that has
living descendants, B. pubescens is only known from
rock beds on Baffin Island.
Such rarity means the actual
age for photosynthesis in
eukaryotes could be much
older, says Andrew Knoll,
a paleontologist at Harvard
who was not part of the study. “This
underscores that we still have a lot to
learn about early eukaryote evolution,”
he says.
Lucas Joel
More induced
earthquakes in the
midcontinent
In southern Kansas, there was only
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Researchers now report that the
quakes correlated with the tim
ing and location of wastewater
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another study, a separate group
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that occurred in Arkansas in sum
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were correlated with hydraulic
fracturing and wastewater injec
tion activities.
Rubinstein et al., Bulletin of the Seis
mological Society of America, February
ȶȉȦȁ 0ERWEW Yoon et al., Journal of
Geophysical Research: Solid Earth,
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TEKIȦȮ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
News
Rising waters sink seafloors
P
redicting how much the ocean
surface will rise in the coming years requires complicated,
global-scale bookkeeping of the
many factors that affect sea levels. In a
new study, scientists have, for the first
time, quantified the role of ocean-bottom
deformation — the gradual deepening of
ocean basins under the weight of more
water — in both global and regional sealevel rise, an effort that may help produce
more accurate sea-level projections.
Sea levels are rising due to two main
factors: As the ocean absorbs excess heat
from the atmosphere, seawater expands
and increases in volume; and as glaciers
and ice sheets melt, the additional freshwater boosts both the volume and the
mass of the ocean.
“As the mass of the oceans gets
heavier, the ocean bottom deforms under
the weight,” says Thomas Frederikse, a
geophysicist at the Delft University of
Technology in the Netherlands and lead
author of the new study, published in
Geophysical Research Letters. “Everybody has always assumed that it affects
sea-level rise by only a very small amount,
but we wanted to take a closer look at its
potential contribution.”
For centuries, sea levels have been
tracked using tide gages, and, since the
early 1990s, using satellite-mounted
radar measurements. However, neither
of these methods accounts for ocean-bottom deformation, says Don Chambers, a
physical oceanographer at the University
of South Florida St. Petersburg, who was
not involved in the new study. “It’s not
yet possible to track ocean-bottom deformation directly; it has to be done using
modeling and this study has done a nice
job of demonstrating how to do that.”
Frederikse’s team compiled previously published estimates of mass loss
from glaciers and ice sheets and plugged
those data into established models to calculate the rates of ocean-bottom elastic
deformation. The researchers found that
adding the mass of the meltwater to the
oceans depressed the seafloor around
*WXMQEXIWSJSGIERFSXXSQHIJSVQE
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GLERKIGFIX[IIRȦȟȟȴERHȶȉȦȏEVI
shown here. The weight of added water
has depressed the seafloor globally by
ER EZIVEKI SJ EFSYX ȉȦȴ QMPPMQIXIVW
per year (mm/y) over that time, accord
ing to new research, although the sea
floor across far northern latitudes has
actually risen due to melting ice and
the redistribution of Arctic waters to
areas south. Blue lines in each panel
indicate where local change equals the
average global ocean trend, the values
of which are shown below each panel.
Credit: Frederikse et al., Geophysical
7IWIEVGL1IXXIVW)IGIQFIVȶȉȦȮ
the world by an average of about
2.5 millimeters between 1993 and
2014. “It’s quite a small amount, but
it’s important to those of us who are
trying to bookkeep every aspect of
sea-level rise and understand all of
the processes at work,” Chambers
says. “We’re measuring changes at
the surface of the ocean, but the bottom
is sinking at the same time and we need
to take that effect into account.” The
Arctic is the exception to the overall
trend toward ocean-bottom subsidence,
however: Widespread ice melting and
redistribution of the weight of lost ice
are causing crustal rebound, leading
much of the Arctic seafloor to rise by
1 millimeter per year or more since 1993.
This study is the first to quantify
modern ocean-bottom deformation, but
a similar elastic effect in Earth’s crust,
known as glacial isostatic adjustment, has
long been considered when modeling the
impacts of ice loss after the last ice age,
Frederikse says. That process results in
deformation of both the land as it rebounds
and the ocean bottom as it takes on mass.
But glacial isostatic adjustment occurs
over many thousands of years — Earth’s
crust is still adjusting after the end of
the last ice age about 11,000 years ago —
while the elastic deformation quantified
in Frederikse’s team’s study is much faster,
happening in a matter of hours to days.
Such timescales for deformation aren’t
unheard of, he notes. “There are a lot of
processes that continuously deform Earth.
For example, Earth’s crust deforms by
several centimeters twice a day as the tides
go up and down.”
Overall, Frederikse and his colleagues
found that estimates of sea-level rise
derived from satellite measurements
may be underestimating relative sealevel rise — what we actually experience
along shorelines — by about 0.13 millimeters per year on average around the
world. The team’s next step will be to
incorporate ocean-bottom deformation
into both global and regional sea-level
rise calculations, he says. “We are still
working on refining the sea-level budget,
and this study puts us one step closer to
accounting for all the possible contributing factors.”
TEKIȦȁ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Mary Caperton Morton
News
Lidar preserves record of destroyed theropod tracks
I
n 2011, the first theropod dinosaur
tracks ever discovered in Arkansas
were uncovered at an active gypsum
quarry near Nashville in the southwestern part of the state. Over two weeks,
researchers collected a set of high-resolution digital scans of the trackway that has
now allowed scientists to piece together its
100-million-year-old story, even though
the tracks have long-since been destroyed
by mining operations.
Funded by an emergency RAPID grant
from the National Science Foundation, a
team from the University of Arkansas and
the University of Mississippi used lidar
equipment mounted on a crane above the
trackway to image the site. The tracks,
embedded in a layer of limestone in the De
Queen Formation, were grouped in eight
theropod trackways of varying sizes and
appeared alongside isolated tracks from
various sauropods and other animals.
In a new report published in PLOS
One, the researchers ascribed the
theropod tracks to adult and juvenile specimens of Acrocanthosaurus, a
genus of large, carnivorous dinosaurs.
The discovery represents the easternmost occurrence of Acrocanthosaurus,
extending its known range east by
90 kilometers. Desiccation cracks, salt
crystal casts and interbedded gypsum
also found in the limestone suggest the
tracks were made in a shallow intertidal
mudflat in the mid-Cretaceous.
The De Queen trackway, now viewable online, adds another example to the
growing list of dinosaur and other fossil
trackways preserved using lidar. “These
data not only allow conservation of the
scientific value of the now-destroyed site,
but they also allow unlimited access to
researchers and the public alike,” wrote
Researchers document a theropod dinosaur
trackway at a gypsum quarry in Arkansas.
Credit: University of Arkansas
Brian Platt of the University of Mississippi and colleagues in the study.
Mary Caperton Morton
9QMRIVEPTVSHYGXMSRYTȰTIVGIRXMRȶȉȦȮ
.R ȶȉȦȮ XLI 9 TVSHYGIH EFSYX Ȯȍȶ FMPPMSR SJ VE[ QMRIVEP QEXIVMEPW
according to the U.S. Geological Survey’s Mineral Commodity Summaries
VITSVXVIPIEWIH/ERȴȦ8LIVITSVXGSZIVWQSVIXLERȟȉRSRJYIPQMRIVEP
commodities, such as aggregates and metals, as well as critical minerals
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I
n recent years, many dinosaurs
have gotten a fabulously feathered
makeover, but for the most part,
scientists still aren’t sure what colors the animals were. A new discovery
of a finely preserved feathered dinosaur fossil in China suggests that some
dinosaurs were as brightly colored as
modern-day hummingbirds.
The fossil, described in Nature Communications, represents a new species,
named Caihong juji, which means “rainbow with the big crest.” The evocative
name suits the duck-sized dino, which
sported a bony crest on its head and long,
ribbon-like feathers. An analysis of microscopic color-bearing structures, called
melanosomes, in the feathers suggested
that the feathers were iridescent, similar
to the most colorful hummingbirds.
A reconstruction of the new dinosaur spe
cies, Caihong juji.
Credit: :IPM^EVMQISRSZWOM+MIPH
Museum
“Hummingbirds have
bright, iridescent feathers,
but if you took a hummingbird feather and smashed it
into tiny pieces, you’d only
see black dust. The pigment
in the feathers is black, but the
shapes of the melanosomes that produce
that pigment are what make the colors
in hummingbird feathers that we see,”
said study co-author Chad Eliason of
the Field Museum in Chicago in a statement. “To find the color of Caihong’s
feathers, we compared its melanosomes
with a growing database of thousands of
measurements of melanosomes found in
modern birds.”
Caihong’s feathers were likely used for display and
warmth, but the animal
was not capable of
flight, the researchers
noted. Caihong is also
the earliest-known animal
with asymmetrical tail feathers, an
adaptation found on modern birds’
wing tips that allows them to steer while
flying. “The tail feathers are asymmetrical
but [their] wing feathers [are] not, a bizarre
feature previously unknown among dinosaurs including birds,” said co-author Xing
Xu of the Chinese Academy of Sciences in
Beijing in a statement. “This suggests that
controlling [flight] might have first evolved
with tail feathers.”
TEKIȦȟ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Mary Caperton Morton
News
How Borneo got its elephants
E
lephants may not seem like
islanders, but a small population lives on the Southeast
Asian island of Borneo. How
and when the animals arrived on the
island has long been a mystery. A new
DNA analysis points to colonization at
the end of the Pleistocene, when a land
bridge may have connected Java, Borneo
and Sumatra to the Malay Peninsula and
mainland Asia.
Theories about when and how Borneo’s elephants arrived have typically
fallen into one of two categories: that
humans introduced nonnative elephants
several centuries ago, or that elephants
colonized Borneo hundreds of thousands
of years ago. Historical records show that,
in the 17th century, the Bornean Sultan
was offered a gift of now-extinct Javan
elephants from the Sultan of the Sulu
Islands in the Philippines. Meanwhile,
no elephant fossils have been found on
Borneo to support a much earlier colonization, although previous mitochondrial
DNA studies suggested the Bornean elephant has been separated from its Asian
ancestors for at least 300,000 years.
In the new study, led by Reeta Sharma
of the Gulbenkian Institute of Science in
Portugal and Benoît Goossens of Cardiff University in England, researchers
analyzed samples from 35 Bornean elephants for genetic markers that might
provide clues about the population’s origins. Mitochondrial DNA, along with
computational modeling, pointed to a
third story: that the elephants are neither recent additions to the island nor
ancient denizens, the team wrote in Scientific Reports.
“Our results suggest that the most
likely scenario to have occurred is a natural colonization of Borneo around 11,400
to 18,300 years ago,” Sharma said in a
statement. “This period corresponds to
The Bornean elephant is the smallest sub
species of elephant. This baby is one of
JI[IVXLERȶȉȉȉMRHMZMHYEPWXLEXVIQEMR
in the wild.
Credit: 7YHM)IPZEY\
a time when the sea levels were very low
and elephants could migrate between
the Sunda Islands, a Southeastern Asia
archipelago to which Borneo belongs.
We cannot exclude more complex scenarios, but a historical human introduction
seems very improbable, and so does a very
ancient arrival.”
Mary Caperton Morton
New map of Titan shows moon’s hidden surface
B
efore NASA’s Cassini mission,
which ended in 2017 after
13 years orbiting Saturn, little
was known about the surface of
the planet’s largest moon, Titan, as most
of its features lie obscured under a dense,
opaque atmosphere composed mainly of
nitrogen gas. However, thanks to special
filters that enabled Cassini’s cameras to see
through the haze, the spacecraft captured
high-resolution images of about 9 percent
of Titan’s surface, with 25 to 30 percent
of the moon imaged in lower resolution.
Researchers have now used an algorithm
to interpolate the remainder of the moon’s
surface and create the most complete
global topographic map of Titan yet.
In a study in Geophysical Research Letters, Paul Corlies of Cornell University in
New York and colleagues described some
of the features of the newly mapped moonscape, including low-rising mountains
— none higher than 700 meters — and
two depressions in the equatorial region
that may be either dried-up seas or flows
from cryovolcanoes, which spew methane,
ammonia or water instead of molten rock.
According to the researchers, the map
— which, along with the Cassini dataset,
is available online — should be useful to
scientists studying Titan’s climate, gravitational fields and the evolution of its
surface landforms.
Mary Caperton Morton
Images of Titan captured by NASA’s Cassini spacecraft have been used to create a new
global topographic map of the Saturnian moon.
Credit: (SVPMIWIXEP,ISTL]WMGEP7IWIEVGL1IXXIVW)IGIQFIVȶȉȦȮ(SVRIPP9RMZIVWMX]
TEKIȶȉ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
News
Ice (Re)Cap
F
rom Antarctica to the Arctic; from polar caps, permafrost and glaciers to
ocean-rafted sea ice; and from burly bears to cold-loving microbes, fascinating science is found in every nook and crevasse of Earth’s cryosphere,
and new findings are announced often. Here are a few of the latest updates.
• Scientists studying deposition of
atmospheric pollutants onto the
Greenland Ice Sheet over the last
WM\HIGEHIWLEZIJSYRHXLEX[LMPI
sulfate levels preserved in the ice
correspond with anthropogenic
emissions trends, nitrate levels
HS RSX .R ȶȉȦȍ=SWLMRSVM .M^YOE of
Hokkaido University in Japan and
GSPPIEKYIW GSPPIGXIH E ȟȉQIXIV
long ice core from the Southeastern
Greenland Dome that dates back to
ȦȟȍȮ&JXIVEGGSYRXMRKJSVGSRXVMFY
tions from major volcanic eruptions,
PMOI 5MREXYFS MR ȦȟȟȦ XLI] JSYRH
that sulfate levels have steadily
HIGVIEWIHWMRGIXLIȦȟȁȉWMRPMRI
with reduced emissions from North
America — thought to be the main
contributor to aerosol deposition in
Greenland — as well as from Europe
and Russia. Despite a similar trend
of reduced airborne nitrate emis
sions, however, the team found that
nitrate levels observed in the ice
GSVI VSWI XLVSYKL XLI ȦȟȮȉW ERH
ƵȁȉWTIEOIHMRXLIIEVP]ƵȟȉWERH
have since remained elevated rel
EXMZIXSȦȟȰȉWƳȦȟȁȉWPIZIPW[LIR
emissions were higher than today.
The cause of the nitrate discrep
ancy is not clear yet, the researchers
wrote in the Journal of Geophysical
Research: Atmospheres. They sug
gested that increased deposition
from North American forest fires
may have been the main factor in
XLIȦȟȟȉWTIEOERHXLEXGLERKIWMR
atmospheric chemistry — possibly
related to increased amounts of
dust and sea salt in the air — could
be contributing to longer residence
times for, and delayed deposition of,
nitrate in the atmosphere, thus pro
longing the elevated concentrations
seen in the ice record.
• Increased snowfall over parts of Ant
arctica, resulting from warming air
holding more moisture, may partially
or fully offset the loss of Antarctic
ice from melting, thus mitigating the
GSRXMRIRXƶWGSRXVMFYXMSRXSWIEPIZIP
rise. But few observations are avail
able to assess this potential mitigation
and test climate model projections.
In new research, scientists who stud
MIH E ȦȰȍQIXIVPSRK MGI GSVI XLEX
records annual precipitation over the
TEWXȶȉȉȉ]IEVWMR[IWXIVR6YIIR
Maud Land (QML) in East Antarc
tica, reported that, in recent decades,
XLI VIKMSR LEW VIGIMZIH ȶȍ TIVGIRX
QSVIWRS[GSQTEVIHXSXLITVIMR
dustrial average, while also warming
significantly. Thus, large snowfalls
there in recent years thought to be
ERSQEPSYWEVIEGXYEPP]TEVXSJEPSRK
IVXIVQXVIRH[VSXIBrooke Medley
of NASA’s Goddard Space Flight Cen
ter in Greenbelt, Md., and colleagues
in Geophysical Research Letters.
Based on their observations from the
ice core and from temperature data,
they found that some climate model
projections for snowfall and tempera
ture increases in QML are too low,
suggesting the models may under
estimate the potential of increased
precipitation in QML to counteract
WIEPIZIPVMWI8LIVIWIEVGLIVWRSXIH
that more records of snowfall and
temperature from across the conti
nent are needed to assess whether
the trend seen in QML holds for other
parts of Antarctica.
• Soils in Northern Hemisphere per
mafrost regions hold roughly twice
as much mercury as the combined
total of all other soils around the
world, the ocean, atmosphere and
vegetation, according to a new
Researchers studying soil cores from
Alaska estimate that soils in Northern
Hemisphere permafrost regions contain
far more mercury than all other soils
around the world combined.
Credit: National Park Service/C. Ciancibelli
study in Geophysical Research
Letters that offers the first compre
LIRWMZI EWWIWWQIRX SJ WSMPFSYRH
mercury in the far north. Mercury
GER FI XS\MG XS ERMQEPW MRGPYHMRK
humans, so elevated levels in the
IRZMVSRQIRXTSWILE^EVHWJSVREX
ural ecosystems and public health.
Paul Schuster of the U.S. Geological
Survey’s National Research Program
in Boulder, Colo., and colleagues
measured mercury concentrations
MRWSMPGSVIWJVSQȦȴWMXIWMR&PEWOEƶW
interior and North Slope. At each
site, they drilled through the active
PE]IV ƴ [LMGL JVII^IW ERH XLE[W
annually, and is where mercury
that settles out of the atmosphere
binds to soil organic matter and
is eventually buried — and into
the permafrost below. Combining
their results with previously pub
lished measurements from other
locations as well as maps of soil
GEVFSR ƴ E TVS\] JSV WSMP SVKERMG
matter and mercury content — they
estimated the total mercury content
of northern permafrost region soils
XSFIEFSYXȦȰȍȉKMKEXSRWRIEVP]
ȁȉȉ KMKEXSRW SJ [LMGL MW WIUYIW
tered in permafrost. “There would
be no environmental problem if
IZIV]XLMRK VIQEMRIH JVS^IR FYX
we know Earth is getting warmer,”
Schuster said in a statement. “Thaw
ing permafrost provides a potential
for mercury to be released.”
TEKIȶȦ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Timothy Oleson
Feature
Bottomland hardwoods are a predominant wetland type in the
Mississippi Alluvial Valley, the historic floodplain and valley of
the lower Mississippi River.
Credit: U.S. Fish and Wildlife Service
+742+&7284+.18*7
Restored Wetlands Remediate Nitrogen Pollution
3ME-YVWX
N
itrogen giveth and nitrogen taketh away:
It’s been estimated that roughly half
of the world’s population today could
not exist without nitrogen fertilization.
Although land area on Earth remains roughly the
same on human timescales, population continues
to rise, requiring more intensive and rigorous use
of existing agricultural land and the creation of
more agricultural lands to meet the ever-growing
demand for food. One way humanity has supported
population growth is through the manipulation
of nitrogen, a limiting nutrient in terrestrial ecosystems. In 1913, the advent of the Haber-Bosch
process, which artificially converts nitrogen gas
to bioavailable ammonia, revolutionized access to
nitrogen and all but eliminated nitrogen limitation
in terrestrial ecosystems. Now, nitrogen fertilizers
are often heavily applied to croplands to increase
plant growth and productivity.
The problem, however, is that nitrogen fertilizers don’t remain on agricultural lands. Much of
what’s applied is washed into local waterways and
eventually makes its way into larger water bodies. The Mississippi River, for example, delivers
1.5 million metric tons of nitrogen (60 percent of
which is in the form of nitrate) per year to the Gulf
of Mexico. Thus, despite the many benefits of nitrogen fertilization, nitrogen pollution of our aquatic
systems has become pervasive, resulting in a range
*EGLWYQQIVEHIEH^SRIETTIEVWSJJXLIGSEWXSJ1SYMWMEREMR
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concentrations of phytoplankton and sediment.
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of detrimental impacts, from
harmful algal blooms to enorNew
mous dead zones.
Orleans
Wetland scientists have
long suggested that wetlands
— which, because of their
filtration abilities, are some#ȍ
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problem. But few large-scale
Bottom Oxygen (mg/L)
projects (besides those specifically designed for wastewater
management) have been implemented to test this habitat, slowed shrimp growth, disrupted spawning
theory. Now, thanks to a wetland restoration proj- patterns, and the death of aquatic species that can’t
ect in Louisiana that’s been running since 1998, escape the area. In recent years, the Gulf dead zone
scientists have more evidence that restoration and has averaged approximately 15,000 square kilomereconnection of floodplain wetlands can significantly ters. Last year, the dead zone was the largest ever
recorded, at 22,720 square kilometers, or about the
reduce nitrogen delivery to the Gulf of Mexico.
size of New Jersey.
The nitrogen that creates the annual dead zone
The Problem: Nitrogen Delivery to in the Gulf is primarily delivered by the Mississippi
the Mississippi River
River, the longest river in North America. The
One of the better-known signs of nitrogen pollu- Mississippi drains 41 percent of North America and
tion are dead zones — areas where the water contains flows through the middle of America’s breadbasket,
little or no oxygen (hypoxia or anoxia). Dead zones where the majority of crop production and fertilcan be created when excess nitrogen enters aquatic izer application occurs. Approximately 58 percent
systems and causes an exponential increase in algae, of the land in the river’s drainage basin is used for
known as an algal bloom. The subsequent death and agriculture, with more than 7 million metric tons of
decomposition of this organic matter deplete oxy- fertilizer applied annually.
gen from the water column, negatively impacting
This fertilizer input, in conjunction with the
aquatic life.
impacts of more than 72 million people living
While these areas of low oxygen occur around within the watershed, has significantly affected the
the world, one notable dead zone reappears each water quality in the river and resulted in a dramatic
summer off the coast of Louisiana in the northern increase in its nitrate load in recent years. Prior to
Gulf of Mexico. Hypoxic water creation in the Gulf 1972, the river’s average yearly nitrogen export
is primarily driven by excess nitrogen delivery, was about 300,000 metric tons; since 1980, that
specifically nitrogen in the form of nitrate. Hypoxic average has hovered around 1.5 million metric
water in the northern Gulf results in the loss of fish tons per year.
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Wetlands can remove nitrate from river water quickly and easily,
together, it would be several years, if not a decade or
more, before these solutions would have a significant
effect on nitrate pollution. Moreover, none of the
solutions would address the issue of legacy nitrate
already existing in soil, which would take more than
30 years to flush from the Mississippi River Basin,
even if all fertilizer application were stopped today.
Fortunately, there’s something that can remove
nitrate from river water within days and is relatively
low maintenance, cost effective and sustainable:
wetlands. And, luckily, Louisiana has a lot of them.
so scientists and environmental groups are working to restore as
many as possible, including this one near Lake Chapeau, Terre
bonne Parish, Louisiana.
Credit: 34&&7IWXSVEXMSR(IRXIV*VMO>SFVMWXc
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In 2015, the Mississippi River/Gulf of Mexico
Hypoxia Task Force — a committee of representatives
from federal agencies, including the Environmental
Protection Agency and NOAA; state agencies from
a dozen Mississippi River states; and the National
Tribal Water Council — established a goal to reduce
the amount of nitrate being delivered to the northern Gulf by 20 percent by 2025, to reduce the size
of the dead zone.
Although solutions exist that can help curb nitrogen input to the Gulf, such as reducing agricultural
fertilizer input and setting criteria for maximum
nitrogen export to the Mississippi, getting all
31 states in the river’s drainage basin to agree on a
plan is challenging. And even if it were possible to get
all states and their agricultural stakeholders to work
The Solution to Pollution:
Filtration Through Wetlands
Once deemed wastelands, to be used as receptacles for trash or as areas where water could be
drained to create usable land, wetlands are valuable
natural filters that can significantly reduce water
nitrate concentrations through denitrification, a
process mediated by microbes that converts nitrate
back to inert nitrogen gas. Wetlands are such excellent converters of nitrate because they often contain
the ideal conditions for denitrification: an abundance
of carbon and low-oxygen conditions.
In Louisiana, a predominant wetland type in the
Mississippi Alluvial Valley is bottomland hardwoods
(BLHs). BLHs are forested wetlands located within
the riparian zones of large rivers and streams in the
Southeast and South-Central U.S. that experience
alternating wet and dry periods, depending upon the
Bottomland hardwood forests (shown here during wet and dry
seasons) are typical throughout the U.S. Southeast, including
the Mississippi River Valley. The photo at left shows the control
site in the Ouachita River Valley, to which researchers compared
restoration efforts at Mollicy Farms.
Credit: PIJX3ME-YVWX EFSZITYFPMGHSQEMR
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river’s water level, or stage. BLHs provide a plethora of ecosystem services and functions, including
habitat for terrestrial and aquatic wildlife, flood protection, carbon sequestration and, most importantly
in terms of hypoxia, water quality improvement by
nutrient retention and removal. In an unaltered
system, spring floods of the Mississippi River would
overflow the natural banks onto the floodplain,
where wetlands would denitrify the water before it
reached the Gulf. Historically, the river had abundant
floodplain wetlands, but the system has been altered
such that floodplains are no longer sufficiently connected to the river.
Almost 80 percent of the BLHs in the lower Mississippi Alluvial Valley have been degraded, primarily
through the harvesting of timber and clearing of land
for agriculture, reducing BLH cover from 9.7 million
to 2.1 million hectares since European settlement
began. Along with the degradation and conversion
of floodplain wetlands came the construction of
2,700 kilometers of levees along both sides of the
lower Mississippi River, which have limited the area
of floodplain interacting with river floodwaters by
90 percent since the 1700s. As a consequence of this
channelization, much of the Mississippi River is now
funneled almost directly into the Gulf, transporting
nutrients into the northern Gulf and helping trigger
hypoxia. So, even when floodplain wetlands are
intact and available, many rarely receive water from
the Mississippi or its tributaries, creating a missed
opportunity for nitrate removal.
Mollicy Farms was once a bottomland hardwood forested wetland,
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Credit: Nia Hurst
The Ouachita River runs between Mollicy Farms
(cleared area at left) and the adjacent control site.
Credit: TNC, Steve Hasse
One solution to this pressing problem sounds
simple: Restore floodplain wetlands and reconnect
them to rivers so they can perform necessary nutrient removal. But can this type of restoration really
be successful? And how long would it take to work?
The Proving Ground:
Mollicy Farms, Louisiana
A great opportunity to test the use of restored
floodplain wetlands to reduce nitrate loads arose in
northern Louisiana at Mollicy Farms — a 6,475-hectare site in Morehouse Parish, La., in the Upper
Ouachita National Wildlife Refuge. It is situated on
the east bank of the Ouachita River, a tributary of
the Mississippi River.
Originally a BLH, Mollicy Farms was cleared for
row-crop agricultural production in 1969, and a
27-kilometer-long, 9-meter-high levee was built to
protect the farm from flooding, essentially disconnecting the site from the adjacent Ouachita River. By
1997, the Nature Conservancy (TNC) had acquired
most of the site and, by 2001, had replanted more
than 3 million bottomland hardwood trees. Now
part of the U.S. Fish and Wildlife Service Upper
Ouachita National Wildlife Refuge, Mollicy Farms
is the largest floodplain reconnection and BLH
reforestation project in the Mississippi River Basin.
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Mollicy Farms is the largest
floodplain reconnection and
bottomland hardwood refor
estation project in the Missis
sippi River Basin.
Credit: Joseph Baustian
Managers planned to breach the levee surrounding Mollicy Farms in 2010, but a high flood year in
2009 did half the work for them by breaking through
the levee in two places. It was the first time the site
had free access to the adjacent Ouachita River in
decades. The managers finished the job the next
year by breaching the levee in two additional places,
facilitating water movement in and out of the site
and restoring floodplain functionality. However,
after 25 years of farming at Mollicy, it wasn’t possible to return the natural water flows at the site
to pre-disturbance conditions, mostly because of
the exorbitant expense. But the connection to the
the site was capable of removing nutrients. That’s
where wetland scientists came in.
We needed to determine the nitrate reduction
potential of Mollicy Farms compared to a natural
control site, what its contribution to the removal of
nitrate from river floodwater would be, and whether
the restoration and reconnection of floodplain wetlands could have a significant impact on reducing
nitrate export to the northern Gulf of Mexico.
In summer 2015, Louisiana State University
wetland biogeochemist John White (my master’s
advisor), TNC wetland ecologist Joseph Baustian and
I collected intact soil cores from both Mollicy Farms
An aerial view (far right) of
researchers, including the author
(right), collecting soil cores from
Mollicy Farms and the control
site to compare nitrate reduc
tion rates and related biogeo
chemical properties between the
X[ScPSGEXMSRW
Credit: both: Joseph Baustian
river — along with the recreation of networks of
streams, bayous and wetlands previously isolated
from the surrounding land to retain water — helped
to establish a hydrologically functional floodplain.
However, although BLH vegetation had been
planted and water flows between Mollicy and the
Ouachita restored, the restoration of biogeochemical functioning and the wetland’s ability to remove
nitrate had yet to be investigated. Given that TNC’s
restoration goal for Mollicy Farms was to restore
site functionality, it was important to determine if
and a nearby natural control site to compare nitrate
reduction rates and related biogeochemical properties at the two sites. We measured nitrate reduction
rates by removing site water from the surface of the
soil cores and replacing it with a 20-centimeter-deep
solution containing 1 milligram of nitrate per liter,
then measuring nitrate loss in the water column over
TEKIȶȰ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
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two weeks. We also measured microbial biomass, or
the abundance of soil microbes, which serves as an
indicator for soil health and carbon mineralization.
$GGLWLRQDOO\ ZH DQDO\]HG ƺJOXFRVLGDVH HQ]\PH
activity, which also serves as a proxy for carbon
mineralization and carbon quality.
We found that the soil nitrate reduction rate at
Mollicy Farms was 11.8 ± 3.37 milligrams of nitrate
per square meter per day, while the reduction rate
at the control site was 16.4 ± 8.10 milligrams of
nitrate per square meter per day. Although the Researchers found that restoration and hydrologic
nitrate reduction rate at Mollicy Farms was lower reconnection of Mollicy Farms to the Ouachita River
than that at the natural site, there was only a 28 per- produced a positive effect on water quality in the
cent difference in reduction between the sites, Ouachita and also the Mississippi.
which demonstrated that hydrologic restoration has Credit: Erika Nortemann, TNC
improved the ability of Mollicy Farms to remove
nitrate from the Ouachita River.
of nitrate from the Ouachita River every year. If a
However, both microbial biomass and soil enzyme standard 15-pound bag of fertilizer contains 28 peractivity were significantly lower in Mollicy Farms cent nitrogen, the average annual nitrogen removal
(82 percent and 65 percent lower, respectively) com- by Mollicy Farms would be equivalent to more than
pared to the natural site. The discrepancy between 25,200 bags of fertilizer.
different soil characteristics at the restoration site
This is just a drop in the bucket, however. The
versus the natural site highlights that not all soil restoration and hydrologic reconnection of Mollicy
functions will follow the same rate of recovery. Farms alone will not significantly reduce nitrate
Even as microbial biomass and enzyme activity are loading in the Mississippi River or nitrate delivery
much lower at Mollicy Farms, nitrate reduction is to the northern Gulf of Mexico, but it can serve
relatively high, despite dampened related soil con- as an example for future floodplain restoration
ditions. This suggests that while some factors (like projects. TNC and the Lower Mississippi River
nitrate reduction) may rebound quickly at a restored Conservation Committee have identified more than
site, others may take longer to recover.
300 additional, albeit smaller, sites along the Mississippi River Basin that are
Overall, we found that
suitable for restoration, with
the restoration and hydrologic reconnection of Mollicy
some sites being designated
Farms to the Ouachita River
specifically for hydrologic
has produced a positive effect
restoration. Combined, these
restoration projects could go
on water quality in that
a long way toward reducing
river and, consequently, the
nitrogen loading in the Gulf.
Mississippi River. Based on
the average nitrate reduction rate in Mollicy Farms
Hurst is a lab manager and
soils, the five-year average
research assistant at the Uni
of annual flooding days at
versity of Central Florida, where
the site (105 days), and the
she researches biogeochemical
size of the area that is likely
responses to restoration. Part of
to flood when the Ouachita
her master’s research at Loui
siana State University focused
River reaches bank-full stage
(60 percent, or 3,874 hectares), The Mollicy Farms restoration project is now on Mollicy Farms. Research on
our data show that Mollicy part of the U.S. Fish and Wildlife Service this topic was published in the
Farms’ soils can remove an Upper Ouachita National Wildlife Refuge.
Soil Science Society of America
average of 48.1 metric tons Credit: Erika Nortemann, TNC
/SYVREPMRcȶȉȦȰ
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The enormous Slumgullion landslide in
southwestern Colorado has been mov
ing — sometimes imperceptibly slowly
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Credit: ;MPPMEQGLYP^9,
SLUMGULLION
Colorado’s Natural “Lab” Offers Insights Into
Landslides Worldwide
Jane Palmer
I
n southwestern Colorado, a centuries-old “laboratory” looks out on the snowy peaks of the Lake
City Caldera in a remote section of the San Juan
Mountains. The lab’s scientists don’t wear white
coats, but Gore-Tex and hiking boots, and they don’t
work inside a building but on a 6.8-kilometer-long
mishmash of red, brown and yellow earth topped
with boulders, ponds and tilted spruce. Early settlers
to the region called the mass Slumgullion, after an
“everything-but-the-kitchen-sink” stew, with “slum”
being an old word for “slime” and “gullion” an English
term for “cesspool.”
Slumgullion was first thought to be a massive
train of debris deposited by glaciers or avalanches.
It took a notorious cannibal to correctly describe the
morass as a landslide. In December 1873, prospector
Alferd Packer and five colleagues embarked on an
expedition through the San Juan Mountains only
to be snowbound by particularly harsh conditions.
The truth of what ensued will never be known, but
Slumgullion was first thought to be a large avalanche or glacial
HIFVMW TMPI 'YX MR Ȧȁȁȴ E RSXSVMSYW TVSWTIGXSV HIWGVMFIH MX
as a big landslide of yellowish clay — and his description was
WSSRcGSRJMVQIH
Credit: Jane Palmer
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Scientists have been studying every fault,
fold, crack and crevice on Slumgullion for
several decades, The above two images
show the landslide headscarp in hydro
XLIVQEPP]EPXIVIHZSPGERMGVSGOW XSTVMKLX
also shows a talus pile near the head of
the moving part of the landslide. The two
images at right show parts of the middle
of the landslide. Left: a furrow created by
XLI WXVMOIWPMT JEYPX EX XLI WSYXLIVR IHKI
of the landslide with moving ground at the
left and stationary ground at the right. Right:
the hummocky surface and tilted trees near
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Credit: all: ;MPPMEQGLYP^9,
historians think that Packer killed his comrades and
then ate them to survive until the spring. In 1883,
Packer admitted to leaving his dead comrades by a big
landslide of yellowish clay, an accurate description
of Slumgullion’s geology.
Scientists soon confirmed that Slumgullion was,
in fact, an enormous landslide, albeit a slow-moving
one: It doesn’t crash down the hillside as a mass
of rocks, earth and debris. Rather, it creeps along
— imperceptibly to casual observers — at about
a centimeter a day, sometimes faster, sometimes
slower. And research suggests it’s been doing this
for at least 300 years.
As such, the site provides a great opportunity for
scientists to study what causes landslides to move,
stop, speed up or slow down. Such research has
allowed scientists to investigate slope stability and
improve models that evaluate the potential threats
posed by landslides all over the world — whether
slow-moving like Slumgullion, or fast-moving like
the one at Oso, Wash., in 2014.
“Slumgullion is arguably the most-studied slowmover in the world, almost definitely in the U.S.,”
says William Schulz of the Landslide Hazards
Program at the U.S. Geological Survey (USGS) in
Golden, Colo. It’s not the sort of slide that’s over in
a day, he says, so it’s possible to learn a lot from it.
Studying a slow-motion landslide allows
researchers to develop new hypotheses and test them
repeatedly, Schulz says. And that’s just what they’ve
been doing at this natural landslide laboratory since
the late 1800s.
Scientists Start Studying
Slumgullion
The first known scientific paper describing
Slumgullion appeared in the U.S. Geological and
Geographical Survey Annual Report in 1874. Then,
in the late 1950s, USGS scientist David J. Varnes,
known for establishing the international standards
for landslide classification, first visited the slide.
Along with colleagues, Varnes measured the movement at several places on Slumgullion and found that
its velocity at a given spot was roughly inversely
proportional to its width at that location.
Further studies in the 1950s and 1960s, in which
scientists pounded wooden stakes into the slide and
came back weeks or months later with tape measures,
helped determine how much the earth had moved.
Simultaneously, the researchers recorded rainfall
between measurements.
By the 1990s, USGS began to step up its investigations of Slumgullion; researchers were keen to
TEKIȶȟ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
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Landslide deposit
Area of active
landslide
Lake City
better understand the controls on landslides, and
Slumgullion was considered a good natural laboratory that was relatively convenient to the USGS
Landslide Hazards Program headquarters. USGS
scientists mapped every fault, fold, crack and crevice
they could find on Slumgullion while also repeatedly
photographing hundreds of points on the landslide
by air over a five-year interval.
Slumgullion
landslide
Slumgullion Pass
The Nature of the Beast
Nearly all landslides consist of three basic parts:
a head at the top of a slide, the middle and the
downslope end, known as the toe. Slumgullion
snakes 6.8 kilometers from its headscarp, the steep
cliff that marks the upslope limit of where the hillside
originally gave way, through the Oligocene-Miocene
volcanic rocks exposed on the flank of the Lake City
Caldera, to its toe, with widths varying from a skinny
200 meters in some parts to 1,000 meters in others.
Radiocarbon dating reveals that about 700 years
ago, the landslide surged into action, damming the
Lake Fork of the Gunnison River to form Lake San
Cristobal, the second-largest natural lake in Colorado. Only part of the slide is still actively inching
along, a 3.9-kilometer-long stretch consisting of an
estimated 20 million cubic meters of earth. Radiocarbon and tree-ring data indicate that this active
section, which is approximately an eighth of the
COLORADO
ȉ
Kilometers
A landslide consists of a head, a middle and a toe. Slumgullion
WXEVXIHQSZMRKMRIEVRIWXȴȉȉ]IEVWEKS8SHE]SRP]TEVXSJXLI
WPMHI MW EGXMZIP] QSZMRK E ȴȟOMPSQIXIVPSRK WXVIXGL GEVV]MRK
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Credit: K. Cantner, AGI
volume of the original slide, has been moving for
the last 300 years.
This mass doesn’t move the same speed all the
time. In the dead of winter, its movement is barely
perceptible even to precision instrumentation; at
other times, parts of the slide have moved at more
than 2 centimeters a day.
Nonetheless, during the last three centuries,
Slumgullion has always been moving, its slow creep
taking it between about 2 and 7 meters a year. While
many slow-moving landslides move intermittently
over short periods of time, perhaps during a particularly wet year or series of wet years, Slumgullion
never seems to stop. “The fact that it chugs along day
after day, year after year, is very impressive,” says
Rex Baum of the USGS Landslide Hazards Program.
The Mechanisms of Motion
PYQKYPPMSRKSXMXWWXEVXEFSYXȮȉȉ]IEVWEKS[LIRMXHEQQIH
the Lake Fork of the Gunnison River to form Lake San Cristobal.
Credit: Jane Palmer
ȍ
The combination of data from the USGS maps
compiled over the years revealed that the slide wasn’t
just a single lump of earth moving in unison. Rather,
it consisted of about a dozen independent blocks,
each of which can move at different rates. “When
you put the data together, you’ve got this really nice
kinematic map that shows how all those [blocks]
are working together,” Schulz says, “What’s following, what’s blocking, what’s leading the procession,
for example.”
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Water is retained in
landslide deposits
Many patterns of motion Clay-rich
found at Slumgullion have hard-to-permeate
slip layer
now been observed elsewhere. At other slides, for
example, scientists have
found extension, or stretching, in the upper parts and
shortening in the lower parts,
similar to what they mapped
at Slumgullion. “That gives
us some clues about the distribution of stresses within the
slide and can be used to better
understand the mechanisms of West
motion,” Baum says. “It means
we are able to improve the accuracy of stability
analyses of the slides.”
Sleuthing out the moving parts of a slide can
ultimately help scientists determine how to mitigate
impacts from a potentially damaging landslide. “By
identifying which parts are less stable, it helps to
pinpoint where you would concentrate your efforts
in trying to stabilize the slide,” Baum says. The
Ponds remain stationary
Landslide deposit
Basal topography
East
Ponds atop the landslide helped researchers reveal the topog
raphy beneath the slide: The appearance of the ponds changes
over the years as the landslide moves, but the ponds themselves
do not move. The locations of the ponds indicate depressions in
the basal topography.
Credit: K. Cantner, AGI
studies at Slumgullion have shown that one of the
most important tasks when assessing a new slide
is to map its kinematics — because different parts
of a landslide often move at different speeds. “If
you’re going to try to mitigate anything, you have
to understand what’s happening first,” says Jeff Coe
of the USGS Landslide Hazards Program.
Nature Versus Nurture
9WMRK SRXLIKVSYRH QETTMRK ERH ,5 HEXE LIPTW
researchers determine how Slumgullion is moving.
Credit: Jeff Coe, USGS
The nature of a landslide — its physical characteristics and the landscape on which it sits — and
the “nurturing” environmental conditions combine
to drive a particular landslide’s activity. On the environmental side, Coe and his colleagues have further
investigated how water affected the Slumgullion
slide. From July 1998 to March 2002, the researchers
measured the velocity of Slumgullion throughout the
year. They found that the landslide moved fastest in
late spring and summer, up to 2.4 centimeters per day
in places, and slowest in the depths of winter when
it moved less than 0.1 centimeter per day. Following
on from previous work, Coe hypothesized that the
slide’s movement is triggered by higher groundwater
levels, an idea confirmed by GPS and extensometer
data (which also measures the movement of material). And higher groundwater levels are directly
related to seasonality in this montane region.
TEKIȴȦ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
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These ponds on the surface of Slumgullion show the basal
topography. As the landslide material moves downhill, the ponds
change shape. The two tilted pine trees (circled in the bottom
four images) can be used for reference.
Credit: all: Jeff Coe, USGS
In winter months, water is less available to the
landslide material because it is stored as snow and
ice and doesn’t soak into the ground as much. In late
spring, snow on the surface of Slumgullion melts,
and, even when the ground is frozen, the broken-up
nature of the slide means that open fractures and
conduits exist for surface water to seep toward the
water table. When groundwater levels are higher,
there’s more water in the gaps between the landslide
material, so pore pressures increase. “This pressure
increase drives the landslide to speed up,” Coe says.
Similarly, he says, in summer months, seasonal
thunderstorms boost water levels in many, if not
most landslides, he says. “So it is water that really
controls the rate of landslide movement.”
Nonetheless, the relationship between moisture
and motion isn’t exactly the same for all landslides,
in part because of the “nature” side of the equation.
In addition to the many blocks or units that usually make up a whole landslide, another important
internal factor that can influence a slide’s movement
is the shape of the stationary land that lies below the
slide. But determining the shape of this basal surface
can be a tricky endeavor, Coe says.
“The best way to determine the shape is by drilling
and trenching, but the cost of doing that work can
be prohibitive,” Coe says. Luckily, at Slumgullion,
the scientists found more accessible clues as to what
lies beneath the surface. When Coe tracked the slow
slip of the landslide between 1998 and 2007, he found
something odd: The ponds on its surface changed
shape but stayed in place, even as the slide material —
including the trees — moved on downhill. “The slide
just keeps whipping on through, but the pond stays
put,” Schulz says. This was the first indication that
what was happening on the surface reflected what
the slide looked like at the base 13 meters below.
Coe inferred that for these ponds to stay in one
place, the landslide is most likely moving over an
irregular slip surface. It helps to picture the base as
an undulating surface, not flat but one with bumps
and valleys, Coe says. As landslide material moves
over the top of that undulation, it also goes up or
down, reflecting the topography of the base. “Every
time it goes down, that’s a depression, not only at
the bottom of Slumgullion, but also on the surface
of the slide,” Coe says. “The topography is translated
from bottom to the top: Bumps on the bottom are
bumps at the top, depressions on the bottom are
depressions on the top.”
The depressions on the surface tend to fill with
water, forming ponds. And since the depressions on
the underlying hillslope don’t move, the locations of
the ponds remains the same. “Once we saw what was
going on, it all made sense,” Coe says.
And when the scientists realized what was happening at Slumgullion, they knew that troughs,
undulations, depressions and other features on other
slides could also yield valuable information about
their bases. If geotechnical engineers are trying
to mitigate a slide, the industry standard requires
boring holes to determine how deep the slide is,
TEKIȴȶ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
Atmospheric pressure changes, caused by the regular daily cycle
in the sun’s heating of the atmosphere coupled with the moon’s
gravitational pull that causes atmospheric tides, seem to affect
Slumgullion’s speed. Researchers found that each afternoon,
when the atmospheric pressure is lower, Slumgullion speeds
up. During the night, when the converse is true, it slows down.
Credit: ;MPPMEQGLYP^9,
and how that depth varies across the slide. So, while
they’ll still have to bore holes, if they “can make
interpretations based on surface features, that helps
interpolate between borings,” Baum says, and “that
can save some money.”
By Land and By Air
Today, USGS has three sites on the slide where
scientists continuously monitor its movement,
near-surface stress, groundwater pressure and
weather conditions. The scientists use these data to
pick apart the complex interplay between rainfall,
snowmelt, groundwater pressure, stress propagation
up and down the landslide, and the landslide’s speed.
Ground-based interferometric synthetic aperture radar (InSAR) is helping USGS scientists and
collaborators measure Slumgullion’s sensitivity to
rainfall. InSAR showed that a mere quarter of a
millimeter of rainfall can cause the ground to speed
up by a factor of five in just a few hours. The root of
this sensitivity lies in the height of the groundwater
table, which sits just a meter below the surface in
many locations of Slumgullion, especially during
the wet season, and the effect
of rainfall on the strength of
faults along the edges of the
slide, Schulz says. Infiltrating groundwater can lead to
fast changes in groundwater pressure and trigger an
acceleration of movement.
“Since it’s moving, any upset
to the force balance [acting
on the landslide] can have
an immediate effect,” Schulz
says. And that should be the
case for any moving landslide,
whether slow or fast, he says.
Another intriguing factor
that seems to affect Slumgullion’s speed is changing
atmospheric pressure. Like
Below: Scientists use a variety of instruments to monitor landslide
QSZIQIRX MR WMXY TSVI[EXIV TVIWWYVIW ERH QIXISVSPSKMGEP
conditions.
(VIHMXPIJXX[S/ERI5EPQIV VMKLXX[S/IJJ(SI9,
TEKIȴȴ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
,VSYRHFEWIH MRXIVJIVSQIXVMG W]RXLIXMG ETIVXYVI
radar is helping researchers measure the slide’s reac
tivity to rainfall.
Credit: Jeff Coe, USGS
the twice-daily tidal cycle caused by the moon, the
sun’s daily heating of the atmosphere coupled with
the moon’s gravitational pull causes atmospheric
tides, which are daily highs and lows in atmospheric
pressure. To most people, this change in pressure is
barely perceptible and certainly not visible, but even
these subtle oscillations can influence Slumgullion’s
movement, Schulz says.
Using aboveground pressure transducers on the
land surface to measure the atmospheric pressure
and extension transducers to measure the movement,
Schulz found that each afternoon, when atmospheric pressure is lower, Slumgullion speeds up.
At night, when the converse is true, it slows down.
As the atmosphere extends into the subsurface soil,
rapidly decreasing atmospheric pressure from the
daily fluctuations can reduce the base load, decreasing the slide’s resistance and increasing its speed.
Schulz’s mathematical model of atmospheric
tide-induced movement could also apply to other
landslides, he says, and indicates that fast-moving
storm systems, which bring about rapid pressure
variations, could also influence landslide activity
in the short term. When weather or storm systems
persist for days or longer, they could additionally
influence the slide’s movement. For example, low
atmospheric pressure transmitted to the groundwater table eventually results in lower pore-water
pressure at the landslide’s base, strengthening and
slowing the slide, Schulz says. High-pressure systems
could have the opposite effect.
Scientists are also studying landslide deformation
and movement from the air. Using Uninhabited
Aerial Vehicle Synthetic Aperture Radar (UAVSAR),
Eric Fielding from NASA’s Jet Propulsion Laboratory
and his colleagues have reconstructed the full
three-dimensional motion of Slumgullion and
gleaned how it deforms at different depths. The
team’s findings confirmed the deformations seen
previously with GPS, the layout of the kinematic
blocks, and the slower movement of the slide in the
winter months. But, in contrast to earlier estimates
of about 13 meters for the average depth of the landslide, Fielding’s team’s work suggested the average
depth is only 7.5 meters.
The landslide has also proved a useful testing
ground for new technologies, like UAVSAR and
spaceborne InSAR, which can be used to study earthquakes as well as landslides. “We always work with
the people who are making measurements on the
ground, so we can calibrate our radar observations
with the ground observations,” Fielding says. “Then
we can apply these techniques to landslides in other
places where there are no ground observations.”
Transferable Results
The investigations at Slumgullion have made a
valuable contribution to landslide science, but there’s
still a lot to learn, Schulz says. For instance, while
scientists have learned much about what makes
Slumgullion tick, it still holds some secrets about
its movement, such as why it has never stopped
moving, year in and year out, for decades on end.
“It’s a little bit of a mystery to me, how it’s able to
keep going,” Baum says.
The rate at which material is being added to the
slide from Slumgullion’s headwall appears slow
compared to the rate of the movement of the active
slide itself, Baum says. “It’s just hard to imagine how
it’s had enough material to keep moving all these
years,” he says.
One explanation appears to be related to a layer
of soft, moist clay that squeezes into the spaces at
the basal surface of the landslide and at the lateral
shear zones. As the slide moves, this clay oozes its
way toward the surface along the lateral shear zones
and coats the side and bottom boundaries of the slide.
Baum observed the earliest evidence of this
mobile clay in landslides in the mid-1980s in central
Utah, and by 1993 scientists had seen it not only in
Utah, but also in Honolulu and at Slumgullion. “We
realized that this … was a widespread phenomenon
occurring in various geologic and climatic settings,”
Baum says.
TEKIȴȏ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
Slumgullion is starting to slow down and will stop moving altogether someday. One reason may be that the
gradual loss of material from the head of the landslide, shown here, means that less material moves downslope
each year, which reduces the driving force on the landslide.
Credit: Jane Palmer
In the 1990s, Baum began to comprehend the
impacts this mobile clay layer had on the instability of slides like Slumgullion. When rain or snow
meltwater soaks into the slide, this water tends to
get trapped inside the main body of the slide, which
is bounded by the slippery clay. It is this “contained”
water that drives the movement of the slide. But
water also seeps into the clay lining. “So it helps
to keep the base of the slide wet and slippery,”
Baum says.
The scientists termed this lubrication and trapping of water the “bathtub effect,” because a clay
lining is less permeable than the material on the
inside or outside of the “tub.” The bathtub effect also
explains the instability of some other slides, and their
ability to be reactivated after sitting stationary. Much
of what’s been learned is “transferable to slow-moving landslides that are similar to Slumgullion, and
there are a lot of those,” Coe says.
Starting to Slow Down
Though Slumgullion continues to move every
day, signs indicate it’s slowing down and will one
day stop moving altogether.
From 1998 to 2010, Coe tracked the movement
of the slide at 18 different locations using GPS and
showed that the landslide was slowing down. In
2010, USGS scientists and Italian colleagues using
ground-based InSAR also found that it was slowing
down, moving at half the speed it did from 1985 to
1990, when it averaged nearly 15 millimeters a day.
Many factors may be influencing the slowing. For
example, Coe says, the gradual loss of material from
the head of the landslide over the decades could mean
that less earth moves down each year, which reduces
the driving forces on the movement. “It looks like
the upper third of Slumgullion is going to be the first
part that stops, essentially,” Coe says.
A second factor may be climate change. Using
historical weather data, Coe determined that in
Colorado, rainfall decreased and temperatures
rose between 1895 and 2010; both factors can
also impact the movement of the landslide. If
these trends continue, Coe suggests, Slumgullion
could stop moving very soon, even within the
next 40 years.
In that event, studies could be conducted on the
impacts of changing climate conditions on landslides. True to form, Slumgullion could continue
to provide valuable information to scientists, even
in its final days.
Palmer (www.tjanepalmer.com/) is a freelance sci
ence journalist based in Eldorado Springs, Colo.
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public health. In a recent trip to Puerto Rico after
-YVVMGERI 2EVME [LIVI ȍȉȉȉȉ PERHWPMHIW GYX SJJ
IRXMVIGSQQYRMXMIWJVSQXLISYXWMHIc[SVPHLIVX[S
FIEXWcMRXIVWIGXIH
TEKIȴȍ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
The American Geosciences Institute
GEOSCIENCE HANDBOOK
AGI Data Sheets
Fifth Edition
The American Geosciences Institute
Mark B. Carpenter,
Christopher M. Keane
F
or more than 40 years, AGI’s Data
Sheets have been a critical tool for the
geoscientist in the field, the lab, and the
classroom. For decades its bright orange
cover and three-ring binding were distinctive in the geoscience community. The
book evolved into its current, full-color and
spiral bound format with the 2005 debut
of the fourth edition.
Now AGI has tapped some of the best
minds in the geosciences to produce this
fifth edition. Featuring the contributions of
over 240 experts worldwide in their respective fields, this new, expanded edition is
over 470 full-color pages. Three years of
work went into the Handbook to broaden
its scope across the disciplines. With more
than 170 complete new data sheets, and full
revisions of prior data sheets, over 85% of
the content is either new or revised for the
fifth edition. The Geoscience Handbook is
the quick reference tool for key metrics and
concepts, a guide to cornerstone papers
and recent developments, as well as short
tutorials on topics that may not be familiar
to all geoscientists.
THE GEOSCIENCE
HANDBOOK 2016
AGI Data Sheets, Fifth Edition
Compiled by
Mark B. Carpenter
Christopher M. Keane
Graphics by Kat Cantner
The Geoscience Handbook 2016: AGI Data Sheets,
Fifth Edition
Edited by Mark Carpenter and Christopher M. Keane
$59.99
492 pages
ISBN: 978-0-913312-47-6
TEKIȴȰ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
Wadi Nakl, the Grand Canyon of Arabia, is
just one of Northern Oman’s many highlights.
Credit: Lon Abbott and Terri Cook
Travels in Geology
3478-*7342&3
Stunning Canyons, Towering Dunes and the
World’s Largest Ophiolite
Lon Abbott and Terri Cook
H
ot, off-the-beaten path and situated amid
an oftentimes turbulent region, Oman
may not top many travelers’ lists of desired
destinations. But if you’re into geology, it
should: The small sultanate, itself politically stable, hosts
the world’s biggest and most intact ophiolite, along with
stunning canyons that plunge into turquoise swimming
holes, lush palm oases and Bronze Age tombs, pristine
beaches where endangered sea turtles struggle back to
the sea after laying their eggs, and endless fields of sand
dunes where you can camp beneath the stars. You’ll
come for the ophiolites, and stay for the rest.
Ophiolites, slivers of oceanic crust and upper
mantle that have been shoved onto a continent,
hold special significance for geologists because of
their rarity and the powerful testimony they offer
about our planet’s dynamism. The vast majority of
ocean crust is recycled back into the mantle, and the
occasional bits that are thrust up onto the edges of
continents are typically dismembered and scattered
across the landscape because the tectonic forces
acting on them are incredibly powerful.
But this is not the case in Oman, where the ophiolite layers reveal the complete stack of rock types that
compose oceanic crust. Our family traveled to Oman
last December to see these unusual rocks, which
form the dark hills behind the capital city of Muscat’s whitewashed buildings, medieval fortifications
and vibrant waterfront. We spent seven memorable
days exploring a compact driving loop through the
spectacular Hajar Mountains from Muscat, enjoying
the country’s many scenic and cultural highlights
while never venturing far from the unique rocks
that drew us there.
TEKIȴȁ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
Iraq
Iran
Sohar
Kuwait
Saudi
Arabia
Qatar
Jebel
Jebel Misht Akhdar
United
Arab
Emirates
Al-Ayn
Oman
Eritrea
Yemen
Djibouti
Somalia
Ethiopia
Gulf of Oman
Geotimes
outcrop
Bahla Fort
Jabrin Castle
Arabian
Sea
Nakhl
Mutrah Fort
Muscat
Al Awabi
Bilad Sayt
Al Hoota Cave
Nizwa
Wadi Shab
Al Mintirib
ȉ
km
Sharqiya
Sands
Ȧȉȉ
Tiwi
Wadi Bani
Khalid
:MWMXSVWXSRSVXLIVR4QER[MPPRIIHEGEVƴTVIJIVEFP]EJSYV[LIIPHVMZIZILMGPIƴXSKIXEVSYRH
Credit: both: K. Cantner, AGI
Muscat:
A City Surrounded by Mantle
Like most visitors to northern Oman, we began
our tour in Muscat, a modern city with a long history
as a commercial trading hub. Omanis have been
master seafarers and traders for thousands of years,
sailing their dhows — traditional wooden cargo
ships — to trade with empires that have risen and
fallen in China, Egypt, Europe, India, Mesopotamia
and Persia. A visit to Mutrah, Muscat’s lovely port
area, is an ideal way to get acquainted with modern
Omani commerce, the city’s connection to the sea
and the sultanate’s famed ophiolite.
Mutrah is best known for its harborside souk, a
traditional Arab market whose crowded stalls are
a feast for the eyes, ears and nose as you wander
through the energetic chaos that accompanies the
sales of sparkling jewelry, antiques, colorful textiles,
fragrant spices and bag after bag of frankincense.
From the souk, it’s just a
few meters to the waterfront walking path. To the
north lies the harbor, where
the sultan’s royal dhow is
anchored, as well as a series
of ocean-themed sculptures strung along the shore
of the sparkling Arabian Sea.
Muscat, a city of 1.3 million people, is nestled
amid rugged brown hills whose rocks are a slice of
Earth’s mantle that was obducted (shoved atop a
continent) about 90 million years ago. The ramparts
of the Mutrah Fort, built by the Portuguese in the
1580s, snake up one such ophiolitic hill, and the
watchtower you reach after walking 1.5 kilometers
is perched on another ophiolite promontory. For
still more spectacular views, you can return to the
Mutrah, the waterfront of Muscat, Oman’s capital, is
a great place to stroll between hills of ophiolite and
the sparkling Arabian Sea.
Credit: Lon Abbott and Terri Cook
The ramparts of Muscat’s fort,
built by the Portuguese in the
ȦȍȁȉW VIWX EXST E WPMZIV SJ
Earth’s mantle.
Credit: Lon Abbott and Terri Cook
TEKIȴȟ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Ras
al-Jinz
Feature
Ophiolite Obduction Process
Eurasian continental
crust of Iran
Arabian
Ocean Volcanic
continental Marine
sediment crust arc
crust
Arabian
continental
crust
Eurasian continental
crust of Iran
Oman ophiolite
Cross-section through the Hajar Mountains
Hajar
Mountains
Tectonic
window
Hawasina Group
marine sediments
Arabian Plate
Op
hio
lite
Sedimentary rocks
native to the Arabian Plate
SW
NE
Lush terraces near the town of Bilad Sayt are irrigated
The Oman ophiolite likely formed when oceanic crust was
by traditional canals originally constructed more than
thrust atop the Arabian continental crust as that buoyant mate
Ȧȍȉȉ]IEVWEKS
VMEP IRGSYRXIVIH XLI WYFHYGXMSR ^SRI ERH LEPXIH WYFHYGXMSR
Credit: Lon Abbott and Terri Cook
Today, the ophiolite has eroded and the deep rocks beneath it
EVII\TSWIHXLVSYKLEXIGXSRMG[MRHS[MRXLI-ENEV2SYRXEMRW
Credit: K. Cantner, AGI
souk via the inland, 2.5-kilometer-long C38 Mutrah
Geotrail, which wends its way through barren hills.
The Ministry of Tourism offers a smartphone app
that will guide you to key outcrops along the way.
The ophiolite consists of a sequence of mafic and
ultramafic (dark, iron- and magnesium-rich) igneous
rocks. At the bottom of the ophiolite lie the mantle
rocks, which make up most of the hills above Muscat
and consist of peridotite — a dense, coarse-grained
rock composed of the minerals olivine and pyroxene.
Above the peridotite lies oceanic crust, consisting of
a sequence of rocks that crystallized from the magma
that rose from the partially melted mantle below.
The Hajar Mountains:
&+SYV;LIIP)VMZI,ISEHZIRXYVI
YRWIXFILMRHXLI-ENEV2SYRXEMRWRIEV3M^[E
Credit: Lon Abbott and Terri Cook
One inspiration for visiting Oman was to see
the “Grand Canyon of Arabia.” Locally called Wadi
Nakl — wadi is the Arabic word for a valley — this
stunning canyon is carved into the south side of the
Hajar Mountains, which rise to 3,000 meters elevation
a mere 60 kilometers from the coast. We had two
TEKIȏȉ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
8LI ȦȶXLGIRXYV] 'ELPE +SVX XS[IVW EFSZI ER SEWMW SJ XLI
same name.
Credit: Lon Abbott and Terri Cook
options to get there from Muscat: a relaxing twohour drive on an impeccable motorway or a rugged
four-wheel-drive adventure through Wadi Bani Auf,
which crosses Jebel Akhdar, Oman’s highest massif.
Our teens chose the latter — and we all received a great
introduction to Oman’s world-class geology en route.
Along the 100-kilometer drive from Muscat to
the foothills town of Nakhl, we passed through a
stack of Late Cretaceous through Paleogene marine
limestones. The presence of these rocks reveals that
soon after ophiolite obduction ended, about 73 million years ago, the region sank below sea level, where
the carbonate sediments
that would form these limestones slowly accumulated
until a second uplift event
beginning about 40 million
years ago raised the modern mountains.
The road returns to the
ophiolite as it reaches the
foothills on the way to Al
Awabi, an Omani town
that is surrounded by lush
palm plantations. Here,
where the road turns south
into the heart of the rugged mountains, the rocks
changed from ophiolite to
Mesozoic limestone as we
crossed a thrust fault at the
8LIJSYV[LIIPHVMZIXVMTXLVSYKL base of the ophiolite. These
;EHM 'ERM &YJ JIEXYVIW Ȧȍ TIV limestones, which make up
GIRXKVEHIWWXIITHVSTSJJWERH the Hajar’s core, are native
spectacular views into several slot to the Arabian Plate, havcanyons, including the twisting ing accumulated atop its
basement rocks during a
Snake Gorge.
long interval of tectonic
Credit: Lon Abbott and Terri Cook
8LIWGIRIV]EPSRKXLIȰOMPSQIXIV'EPGSR];EPOMR
Wadi Nakl is reminiscent of the American Southwest.
Credit: Lon Abbott and Terri Cook
quiescence in the region that reigned from about
280 million to 95 million years ago.
That quiet was shattered, however, when the
ophiolite was obducted. For years geologists have
debated how such dense material ended up atop more
buoyant continental crust. Currently, the leading
hypothesis is that oceanic lithosphere attached to
the Arabian Plate began to subduct beneath what
would later become Oman’s ophiolite, in the process
drawing the buoyant Arabian continent down and
closer. When Arabian continental crust reached the
subduction zone, it was too light to be subducted, so a
head-on collision ensued, during which the ophiolite
was plastered onto the edge of Arabia.
Having crossed the thrust fault underlying the
ophiolite, we entered what geologists call a tectonic
window: a view into the stratigraphy of the rocks
below. Uplift of the Hajar Mountains 40 million
years ago created a giant anticline that bent the
ophiolite upward. Subsequent erosion stripped the
ophiolite off the top of the arch, exposing a “window”
into the rocks below. Not far south of Al Awabi,
the pavement ends and the road crosses into older,
metamorphosed sedimentary rocks that underlie the
limestones. These rocks were deposited between
about 750 million years ago — during one of the
“Snowball Earth” events when Earth’s surface nearly
froze over completely — and about 330 million years
ago, when they were metamorphosed during the
assembly of the supercontinent Pangea.
The scenery in Wadi Bani Auf is desolate but
magnificent, and it becomes even more dramatic
TEKIȏȦ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
farther south, where the road crosses back into the
limestones, and where the Hajar grow taller and so
much more rugged that you need a four-wheel-drive
to safely navigate the 15 percent road grades, vertical
drop-offs and narrow shelves precariously perched
beneath the soaring cliffs. Along the way, you can
visit the chasm of Snake Gorge, Arabia’s premier
canyoneering route, as well as Little Snake Gorge,
and our favorite: a hike up a short slot canyon to
the village of Bilad Sayt, which is surrounded by a
green carpet of terraced fields irrigated by a system
of aflaj (canals) constructed more than 1,500 years
ago. Oman’s aflaj are of such cultural significance
that they have been designated a UNESCO World
Heritage site.
After reaching the end of our four-wheel-drive
geoadventure, we drove the very steep road up to
a luxurious “glamping” resort high on the flanks of
Jebel Shams, Oman’s highest peak, where we enjoyed
a spectacular sunset and spent the night at about
Oceanic Crust in All Its Glory
O
ur loop drive through the high
-ENEV2SYRXEMRWFSEWXIHI\GIP
Classic Ophiolite Sequence
PIRX I\TSWYVIW SJ IZIV] SGIERMG
km
Sediments
GVYWXEP PE]IV 4RI KSSH I\TSWYVI
of the sequence of mantle rocks
Basaltic pillow lavas
ERHǼS[W
is found in the hills surrounding
1
Oman’s capital city Muscat. They
Sheeted dikes
consist of a variety of peridotite
GEPPIH LEV^FYVKMXI [LMGL MW XLI
2
T]VS\IRIHITPIXIH VIWMHYI PIJX
Gabbro
behind after basaltic magma is
3
I\XVEGXIH 8LEX I\XVEGXIH QEKQE
forms the oceanic crust, whose
Layered gabbro
characteristic rock sequence is,
4
JVSQFSXXSQXSXSTȦHEVOPE]IVIH
gabbro overlain by massive gabbro
(the intrusive equivalent of basalt
5
that comprises solidified magma
Moho
GLEQFIVW ȶWLIIXIHFEWEPXMGHMOIW
6
(the conduits that transported lava
from the magma chambers up to
XLISGIERJPSSV ERHȴFYPFSYWTMP
7
Peridotite and
low lavas, which form when basalt
associated
YPXVEQEǻGVSGOW
erupts directly into seawater.
8
Even after seeing this fantas
tic sequence, we were compelled
to make a detour to ;EHM /M^^M, a
9
X[SLSYV HVMZI RSVXL SJ 2YWGEXMR
search of what is quite possibly the
10
world’s most astounding outcrop
of pillow lavas: the famed “Geo
times” outcrop, so named after its
photo graced the cover of Geotimes The classic ophiolite sequence is a cross
*&78-ƶWTVIHIGIWWSVMRȦȟȮȍ8LI section through both the upper mantle
WXYRRMRK SYXGVST JIEXYVIW XYFI and the oceanic crust.
shaped blobs of basalt, each taller Credit: K. Cantner, AGI
4RISJXLI[SVPHƶWFIWXI\TSWYVIWSJTMP
low lavas graced the cover of Geotimes,
*&78-ƶWTVIHIGIWWSVMRȦȟȮȍ
Credit: American Geosciences Institute
than a person, intertwined with one
another like a mass of wriggling black
worms. The pillows form when sea
[EXIV UYIRGLIW XLI I\XIVMSV SJ XLI
submarine lava flows while the hot
MRXIVMSVWGSRXMRYIXSI\TERHEWXLI]
fill with lava supplied by the sheeted
dikes below. A similar process is cre
ating pillow lavas along the edge of
Hawaii’s Big Island today.
TEKIȏȶ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
LA & TC
Feature
2,000 meters elevation. The next day it was only
a few minutes’ drive to Al Khateem, the starting
point of the famous Balcony Walk, a 6-kilometer
round-trip hike into spectacular 1,000-meter-deep
Wadi Nakl canyon. The scenery is reminiscent of the
American Southwest, with sheer walls of resistant
limestone alternating with benches carved from
less-resistant shale. The hike ends at the ghost village
of As Sab, which, although it was only abandoned
in the 1970s, resembles an ancient Puebloan ruin.
Medieval Forts and Neolithic Tombs
After descending the south side of the Hajar, we
arrived in the tourist hub of Nizwa, where there are
enough attractions to keep visitors occupied for days.
We visited Al Hoota Cave, which has respectable
stalactites and stalagmites, as well as a nice geology
museum. The scenic drive up onto the Saiq Plateau
passes several spectacular terraced villages famed
for their orchards and rosewater, a perfume made
by steaming rose petals, which Arabs traditionally
sprinkle on the hands of guests after dinner. And
we visited two impressive medieval forts: Jabrin
Castle, built in 1675 by a prominent Omani imam,
and the 12th-century Bahla Fort, one of Oman’s top
sights. Although there are only a handful of interpretive signs, mostly concentrated around Bahla Fort’s
mosque, this World Heritage site is very impressive,
and we all really enjoyed wandering through its maze
of rooms. Our kids eagerly clambered up the many
staircases and ladders, coaxing us to follow them
with descriptions of the far-reaching rampart views.
Meanwhile, we admired the excellent sheeted dike
complex — a distinctive segment of the ophiolite —
on which the fort was built.
Bahla Fort is built atop an impressive sheeted dike
GSQTPI\
Credit: Lon Abbott and Terri Cook
It took us a while to find another highlight of
the Nizwa area, a line of 20 “beehive tombs” constructed between 3,000 and 2,000 B.C. on a lonely
ridgeline above the village of Al-Ayn. Despite being
a World Heritage site, there are no signs marking
the tombs’ location. After searching for an hour,
we finally caught a glimpse of one of the tombs
silhouetted on the skyline. Our frustration gave
way to elation with the realization that we were
alone at this striking site. The area’s Bronze Age
inhabitants constructed the tombs by piling up
desert-varnished sandstone blocks to make 5-to-7meter-high beehive-shaped rooms in which they
interred their dead. The sandstone belongs to the
Hawasina Group, a pile of deep marine sedimentary
rocks that were folded like an accordion as they
were thrust onto the Arabian continental margin
along with the ophiolite.
The grandeur of this site is enhanced by the
nearby countenance of Jebel Misht, a nearly vertical
1,000-meter-high wall of Triassic limestone that
looms above the tombs. Because this limestone
overlies Late Triassic basalt, geologists have concluded that it represents what was once an isolated
seamount, which was decapitated and shoved atop
the continental margin by the overriding ophiolite
during obduction. Burial by the ophiolite, which was
later eroded away at this site, caused the limestone
to recrystallize, making it especially resistant to erosion and explaining why it remains so sheer and tall
today. Thanks to this remarkable geologic history,
it’s Arabia’s premier big wall rock-climbing venue.
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FIILMZIXSQFRIEVXLIZMPPEKISJ&P&]R
Credit: Lon Abbott and Terri Cook
TEKIȏȴ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
Local Bedouin enjoying a break amid the spectacular
Sharqiya dunes.
Credit: Lon Abbott and Terri Cook
First light is magical on the Sharqiya Sands.
possible. Although the plunges down the same steep
faces agitated the butterflies in our stomachs, our
kids giggled the entire time; their only regret was
that we didn’t have another day amid the dunes so
that they could learn to sand-board.
Credit: Lon Abbott and Terri Cook
A Sea of Sand
Like Jebel Akhdar, the southeastern Hajar
Mountains are another large arch uplifted about
40 million years ago during an episode of compression that was likely triggered by subduction of
the Arabian Plate beneath Iran along the Makran
Subduction Zone. The foothills south of these
mountains preserve an especially wide swath of
oceanic lithosphere, including excellent examples
of the layered gabbros that form the base of oceanic
crust. But southeast of the town of Al Mintirib, the
seemingly endless expanse of dark ophiolite finally
ends at a large field of southwest-trending longitudinal dunes called the Sharqiya Sands.
Don’t miss spending a night at one of the many
desert camps scattered throughout the dune field;
our day and night in this sea of sand, partaking in
warm Bedouin hospitality, gazing up at inky black
skies full of twinkling stars, and enjoying a majestic
sunrise and sunset on the dunes, was the highlight of
the trip for our kids. They especially reveled in the
four-wheel-drive “dune bashing” tour, during which
our expert desert driver coaxed the Land Cruiser
up 35-degree dune faces farther than we thought
The moderate hike up Wadi Shab parallels a historic
irrigation canal still used to water date palms and
other crops.
Credit: Lon Abbott and Terri Cook
TEKIȏȏ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
Sea Turtles and Swimming Holes
Another must-see site in northern Oman is Ras
al-Jinz, the easternmost point on the Arabian Peninsula
and the location of one of the world’s most important
nesting sites for endangered green sea turtles. Despite
the loud grumbling from our reluctant kids when we
rousted them at 4 a.m. for the guided tour of the nesting
beach, they admitted the experience was well worth the
effort once they witnessed a mother turtle laboriously
crawl back into the sea after laying her clutch of eggs.
Because the turtles always vacate the beach before
sunrise, visitors are free to wander there on their own
during the day, and we had a wonderful time strolling
along the cliff-backed beach, photographing fresh turtle
tracks in the low morning light.
After relaxing for a day on the coast, we set out
to explore more of the eastern Hajar Mountains,
which are festooned with ancient aflaj. We took a
leisurely stroll up Wadi Bani Khalid to swim at a
deep swimming hole next to a bustling snack bar.
Then we ventured up Wadi Shab, near the coastal
town of Tiwi, a longer but still gentle walk along
The sun’s first rays illuminate fresh tracks made by an
endangered green sea turtle crawling back to the sea.
Credit: Lon Abbott and Terri Cook
one of the World Heritage canals that parallels a
perennial creek with cascading waterfalls and several turquoise-blue swimming holes, all set deep
beneath soaring limestone walls every bit as spectacular as the canyons of the American Southwest.
Wadi Shab, which lies just 100 kilometers southeast of Muscat on a modern motorway, is an easy
half-day trip from the capital. All of the sites we visited
could be reached in a day from Muscat, illustrating
how much geologic diversity — and how many cultural attractions — you can enjoy on even a short visit.
Given the steady stream of alarming news emanating
from the Middle East these days, it’s understandable
that many North Americans are reluctant to venture
there. But Oman is an oasis of stability, and few places
can rival the geologic and scenic splendor northern
Oman packs into such a compact area.
Abbott is a geology professor at the University of
Colorado Boulder. Cook ([[[HS[RȶIEVXLWGMIRGI
Refreshing swimming holes await hikers in the canyon of Wadi Shab.
com) is a science and travel writer based in Colorado
Credit: Lon Abbott and Terri Cook
and an EARTH roving correspondent.
TEKIȏȍ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Feature
Getting There & Getting Around
O
man’s main gateway is Muscat International Airport
(MCT), which offers service to most major Middle
Eastern and European cities. There are no direct flights
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nient to fly through Dubai, Doha, Bahrain or a major
European city. Emirates, Qatar Airways, Gulf Air, Oman
Air and Turkish Airlines are among those that offer con
necting service. The airport is located on the western
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one of the microbuses that depart from the opposite
side of the footbridge that spans the highway outside
the airport.
and some of the most spectacular wadis in the Hajar
Mountains. Leaving paved roads behind is a serious
YRHIVXEOMRK [IFWMXIWWYGLEWtimesofoman.com offer
important safety tips to read before you start. Road signs
are posted in both Arabic and English, and gasoline is
relatively cheap and widely available.
During the winter high season, it’s a good idea to book
accommodations ahead of time, especially during the
holidays. Omani hotels range widely in price, services
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desert camps, there are no real campgrounds, but wild
camping is allowed outside of urban areas as long as
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essary to reach suitable sites.
Oman’s currency is the rial, which is divided into
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a good idea to stock up on cash before you leave the
cities. Most desert camps and rural accommodations do
not accept credit or debit cards.
The weather is typically sunny and mild during the
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ing in summer. The best time to visit is from November
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the Sharqiya Sands.
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A colorful sample of the many wares available at Mutrah’s
souk, or market.
Credit: Lon Abbott and Terri Cook
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northern Oman is by renting a vehicle. The airport offers
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Dune bashing is a highlight of any visit to the Sharqiya Sands.
Credit: Lon Abbott and Terri Cook
TEKIȏȰ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
52nd Annual Meeting
Association of Earth Science Editors
Niagara Falls, New York
September 26-29, 2018
Abstracts deadline: August 15, 2018
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TEKIȏȮ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Geomedia
Books: Solar Eclipses Past, Present and Future
Thomas Berger
O
n Aug. 21, 2017, a total solar
eclipse traversed across the
United States, from the western coast of Oregon to the
eastern shores of South Carolina. I witnessed about one minute and 50 seconds
of totality from Salem, Ore., where the
skies were unusually clear — despite the
wildfires then raging around the West.
In eclipse parlance, totality refers to the
period when the moon — which, in the
most mind-blowing of cosmic coincidences, just happens to be the same
angular size in the sky as the sun — completely blocks the sun’s bright disk and
reveals the tenuous outer solar atmosphere known as the corona.
Even though I’m a solar physicist
and can view the solar corona at will
through any number of ground- or spacebased telescopes, nothing prepared me
for the jaw-dropping beauty of the solar
corona seen with the naked eye during a
cloudless total solar eclipse. I now fully
agree with Fred Espenak, co-author of
“Totality: The Great American Eclipses
of 2017 and 2024,” that “in rating natural
“Totality: The Great American Eclipses of
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wonders, on a scale of 1 to 10, a total
eclipse of the sun is a million!”
The two books reviewed here —
“Totality” and “American Eclipse: A
Nation’s Epic Race to Catch the Shadow
of the Moon and Win the Glory of the
World” by Colorado science writer David
Baron — both capture the historical scientific significance and the excitement that
still exists today in viewing solar eclipses,
particularly those that pass over our own
piece of the planet.
In “American Eclipse,” Baron takes
us back to the Gilded Age and the total
solar eclipse of July 29, 1878 — when the
solar corona, which wasn’t even accepted
as part of the sun’s atmosphere at the
time, was still a mystery. The location
and timing of eclipses were calculated by
hand by the likes of American astronomer
Simon Newcomb, superintendent of the
Nautical Almanac, without the aid of
computers or even reliable clocks. Baron’s
subtitle emphasizes that the Gilded Age
was a time when American scientific
institutions struggled for respect from
scientific leaders in Europe, and many
American scientists of the day viewed the
eclipse as an opportunity to prove their
mettle in the astronomical and measurement sciences.
Taking a character-centric approach,
the book focuses on several scientific
personalities of the time, including University of Michigan Professor James
Craig Watson, America’s foremost
minor planet (asteroid) hunter; Professor Norman Lockyer, the preeminent
solar physicist of the day, discoverer
of the element helium (via solar spectroscopy), founder and editor-in-chief
of Nature, and Britain’s most famous
astronomer to attend the 1878 “American” eclipse; Professor Henry Draper
of New York University, discoverer of
oxygen in the solar atmosphere; and
Vassar Professor Maria Mitchell, one
of America’s foremost astronomers and
“American Eclipse: A Nation’s Epic Race to
Catch the Shadow of the Moon and Win
the Glory of the World,” by David Baron,
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.'3ȟȮȁȦȰȴȦȏȟȏȍȍȉ
strongest advocates for women’s rights
in politics and the sciences, who viewed
the eclipse from just outside Denver,
Colo. Also prominent throughout the
story is Thomas Edison, the famous
inventor of the phonograph and many
other successful inventions, and the
not-so-successful “tasimeter” with which
he, in a personal echo of the nation’s
scientific insecurity at the time, hoped
to measure the temperature of the solar
corona during the eclipse, thus establishing his reputation as a serious man
of science rather than just an inventor.
Baron writes compellingly about the
conditions of the American West in 1878
and what it took for the Draper-Watson-Lockyer-Edison expedition to make
its way by train to the “barren wasteland”
of Rawlins, Wyo., where totality had
been judged most likely to happen under
cloudless skies, and where we meet other
personalities, such as the self-promoting,
alcoholic celebrity of the time, “Texas
Jack.” Baron also captures the courage
TEKIȏȁ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Geomedia
and tenacity of Mitchell in persisting
through absurd obstacles, not least of
which was the prevailing belief that a
woman couldn’t possibly travel on her
own to the Wild West city of Denver, to
carry out a “women’s eclipse expedition.”
Although seemingly not that long ago, it
is amazing to read of the tense encounter
that another eclipse expedition, organized
by Princeton University, had with Ute
warriors just outside Denver, only a year
before their leader, Chief Colorow, would
lead a war against further encroachment
on Native American lands.
The story also reminds us that eminence is no guarantee of scientific acuity.
The famous Professor Watson, primed
with plentiful hubris, claimed with great
certainty to have discovered the long-rumored planet of Vulcan inside Mercury’s
orbit during the eclipse — a claim which
obviously turned out to be bogus. And
the great Professor Lockyer could hardly
contain his scorn for Professor Draper’s
claim of discovering oxygen in the solar
spectrum — a claim that Lockyer thought
ridiculous, but which later turned out
to be correct, not to mention extremely
significant for understanding the link
between the stars and life on Earth.
“American Eclipse” will give readers
a detailed picture of American science in
the Gilded Age, thanks to Baron’s knack
for bringing the past to light through a
grand cast of characters, while also putting scientific discovery in its social and
political context.
After absorbing the history in “American Eclipse,” and perhaps after having
witnessed the Great American Eclipse
of 2017, readers would be well-advised
to start getting ready for the next grand
celestial event to traverse our nation: the
total solar eclipse of April 8, 2024, which
will cross the U.S. from Texas to Maine.
In “Totality,” which looks at both the
2017 and 2024 eclipses, science writer
Mark Littmann and NASA’s Fred Espenak, known as “Mr. Eclipse,” combine
their scientific and writing talents to
produce a full compendium of eclipse
odds and ends, from the psychological
impacts of seeing a total solar eclipse, to
the mythology and history of eclipses, to
tips on safely viewing and photographing them.
For those who possess a time machine
or plan on living forever, the book includes
Espenak’s maps of all solar eclipses in the
United States geographical region from
1492 to 2100, as well as detailed maps of
the upcoming 2024 event. If you want one
book that captures the full range of eclipse
experiences, from the thrill of the chase,
to the science of the celestial alignments
and solar physics behind eclipses, while
focusing on the recent and not-so-faroff events in the United States, this is
that book.
Berger is director of the Space Weather
Technology, Research and Education
Center in the College of Engineering and
Applied Science at the University of Col
orado Boulder.
GOLI
Geoscience Online Learning Initiative
The Geoscience Online Learning Initiative (GOLI) is an initiative
by the American Geosciences Institute, started in cooperation
with the American Institute of Professional Geologists, to provide
a platform for asynchronous, life-long learning and continuing
education opportunities in the geosciences. GOLI consists of live
webinars and self-paced asynchronous online courses. CEUs are
granted by AIPG to individuals attending the webinars or completing the courses. GOLI online courses are brought to you via the
OpenEdX Learning Management System (LMS) through which
learners are able to browse course descriptions, enroll in specific
courses, access content, and complete any course free of charge.
For more information about the Geoscience Online Learning
Initiative visit:
https://www.americangeosciences.org/workforce/goli or
contact Heather Houlton at hrh@americangeosciences.org.
For more information on AIPG and CEUs, visit www.aipg.org.
Sample courses:
t Assessing, Mitigating, and Communicating Flood Risk
t Communicating Cascadia’s Earthquake Risk
t Basics of Seismic Petroleum Exploration for New Hires
t Planning for Coastal Storm and Erosion Hazards
t Best Practices in Mineral Resource Estimation & Reporting
t Fundamentals of Professional Ethics: Elements and Examples
Image credits: left: ©iStock.com/Chris Gramly; right: Zsuzsanna Toth (submitted to AGI’s 2016 Life as a Geoscientist contest)
TEKIȏȟ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Where on Earth?
WHERE ON
EARTH?
SUBMIT
YOUR
PHOTOS!
CLUES
SEE DETAILS BELOW
ʕ The name of this group of eight volcanic islands
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chain of islands in the northern Pacific — was
translated from the Russian name “Ostrova
Chetyre Soposhnye.”
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ʕ When the island group was visited by the U.S.
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center volcano (seen with steam rising from its
peak), which is the tallest and most volcani
cally active in the group, was renamed for the
sitting president.
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Sulphur Mountain in Banff National
Park, Alberta, Canada, hosts a his
toric weather station and is the site
of a former station built to celebrate
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physical Year. Photos by Cassidy
Gallant (right) and Manfred Hauben
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Jason Droboth (Calgary, Alberta, Canada)
David Goldak (Wichita, Kan.)
Morgan Haldeman (West Kingston, R.I.)
Anthony J. Padilla (Vienna, Va.)
Charles Shobe (Louisville, Colo.)
NAME THE ISLAND GROUP & ITS HOST STATE.
Where on Earth was this picture taken? Use these clues to guess
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and send your answer via Web, mail or email by the last day of
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photos to consider for the contest. Find out more about submitting
and clues in EARTH’s monthly digital editions. From those who
your photos at [[[IEVXLQEKE^MRISVK[LIVISRIEVXLWYFQMX, and
answer correctly, EARTH staff will randomly draw the names of
send them to IEVXL%IEVXLQEKE^MRISVK. If we print your photo in
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[[[IEVXLQEKE^MRISVK[LIVISRIEVXL. You can also submit entries
small gift from AGI.
TEKIȍȉ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
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Across
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63. Nerve poison
65. Ashtabula’s lake
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31. “High” time
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34. Comply with
35. Bookbinding
leather
36. Anderson’s
“High ___”
40. Publicity, slangily
41. Critical
44. Eye coverings
46. Reap
48. Bindle bearer
49. Saprolitic?
52. Part of a plane
5Y^^PIWSPYXMSR appears in the Classifieds section.
54. Like “The
X-Files”
6Xϒ[ZLWKVHFW
56. Asian weight
units
57. “What’s gotten
___ you?”
58. Warm, so
to speak
59. NC school
GEOWORD
of the Day
Subscribe at:
www.americangeosciences.org/word
A free service of the American Geosciences Institute.
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TEKIȍȦ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
61. “That’s ___”
62. Black stone
64. “___ to Billie Joe”
Down to Earth
With National Park Service Senior Paleontologist
:MRGIRXcERXYGGM
Terri Cook
W
hen Vincent Santucci
was hired in 1985 to
work as a seasonal
ranger in South Dakota’s Badlands National Park, he assumed
the most formative part of the experience would be sharing his unbridled
enthusiasm for fossils with park visitors.
But as Santucci explored the colorful
badlands on his days off, he sometimes
stumbled across people who were illegally
collecting fossils. Following the first of
these encounters, Santucci raced back to
headquarters to report the illicit activity
with the expectation that the chief ranger
would rush out and arrest the perpetrator.
Much to Santucci’s surprise, the ranger
instead put a hand on his shoulder and
drawled, “You ain’t from around here, are
you, boy?” After several repeat episodes,
Santucci learned that when rangers had
previously caught illegal collectors and
brought them before the local magistrate,
the judge had refused to prosecute, citing
a lack of fencing or signage that clearly
informed the fossil hunters they’d been
on federal land.
Later that same season, on a day that
Santucci describes as the most significant
in determining his career path, the young
ranger discovered two men engaged in
suspicious “shopping behavior” in a
very remote area of the park. Although
one evaded contact with him, the other
— a friendly, grandfatherly gentleman
— greeted Santucci, who was dressed in
plain clothes, and asked if he was having
any luck finding fossils. In the course
of their conversation, Santucci learned
that, although the man realized he was
in a national park and understood that it
was illegal to collect fossils there, he had
done so for 25 years — and, in the process,
become very wealthy. In the man’s mind,
he was “rescuing” fossils that the park
service would otherwise have allowed
to erode away.
After the thief invited Santucci to a
campsite to purchase some of his many
finds, the young ranger sped back to
the office to report the incident to the
chief ranger, all the while bracing to
once again hear the senior officer’s tired
line. This time, however, the chief ranger
realized that Santucci had encountered
a seasoned professional and decided to
mount a response.
Santucci began working undercover,
eventually gathering enough information to have the man arrested. When
the thief was brought before the magistrate and confessed his crimes, the judge
couldn’t simply dismiss the case as he had
done before. Instead, the judge fined him
$50 and sent him on his way. Santucci
was shocked by this outcome, and the
events helped him realize that there was
a much-needed role within the National
Park Service for someone who focused
on protecting paleontological resources.
Once the season was over, Santucci
returned to the University of Pittsburgh
to complete his master’s degree and also
earn a law enforcement commission.
Santucci has since worked as the federal
government’s only sidearm-carrying paleontologist, helping protect our nation’s
fossil resources while stationed at six different national parks over the years. Today,
he serves as the senior paleontologist and
paleontology program coordinator at the
Washington, D.C., headquarters of the
National Park Service. He is the author
of more than 180 publications and the
recipient of numerous distinctions, including the George Wright Society Natural
Resource Achievement Award and the
George and Helen Hartzog Stewardship
Award. Much to Santucci’s delight, two
fossil discoveries — Androcycas santuccii
and Sapelnikoviella santuccii — have been
named in his honor.
Santucci recently spoke with EARTH
about the importance of fossils early in
Vincent Santucci is the senior paleontolo
gist and paleontology program coordinator
at the National Park Service.
Credit: NPS photo
our nation’s history, the most forgotten
national monument and why he has the
world’s best job.
TC: What do you think has been the
most noteworthy fossil discovery in
the U.S.?
VS: If I had to name one, it’d be the
original T. rex found in Montana’s Hell
Creek Formation in 1902. That was the
first one assigned the name Tyrannosaurus rex, and it was a really impressive
specimen that captured a lot of media
attention and sparked the public’s imagination about this ancient world and the
organisms that lived there. The fossil is
also important to me personally because
as a kid growing up in Pittsburgh, I
spent rainy days running around the
Carnegie Museum of Natural History
Dinosaur Hall, where that fossil was
displayed. I naturally gravitated toward
the skeleton and the life-sized T. rex
painting that hung behind it. For many
visitors, that was the focal point of the
museum, like Old Faithful in Yellowstone National Park.
TEKIȍȶ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Down to Earth
TC: What ignited your interest
in science?
VS: During my childhood, my family was big on travel and camping and
education, so we visited national parks
all over the country. When I was 13, my
uncle and I drove cross-country in a little Volkswagen Beetle. After we pulled
into Badlands National Park and read
that it preserves one of the world’s richest deposits of fossilized mammals, we
decided to hike the Fossil Exhibit Trail,
where I saw my first fossil in the wild. It
was a section of jaw with teeth sticking
out of it. Even I could clearly tell that
those were teeth! Seeing a skeleton in a
museum is one thing, but observing fossils in a natural setting within a geologic
context gives it a deeper meaning. It was
very exciting to think about the possibilities of what was preserved in those rocks.
That experience turned me on to geology
and paleontology.
Santucci served as acting superintendent of Tule Springs Fossil Beds National Mon
YQIRX MR 3IZEHE[LMGL[EW HIWMKREXIH MR ȶȉȦȏ XS TVIWIVZI XLI VIQEMRW SJ HMZIVWI
TC: How have you shared your enthusiasm with others?
VS: While working on my master’s
thesis, I was very fortunate to land a seasonal ranger position at Badlands. It was a
real honor to wear the uniform and learn
how the park service provides public
education and outreach. I was able to take
visitors on hikes into the badlands and
share with them my experience of seeing
a fossil outdoors for the first time, and
also help them find fossils on their own.
No matter how common or rare those
specimens were, those individuals were
excited, and I found it very rewarding to
share this sense of discovery with them.
TC: What is your current role within
the park service?
VS: I have the best job in the world.
It encompasses all aspects of the management, protection, interpretation,
scientific study and curation of fossils,
so on any given day I’m dealing with a
wide variety of issues. Our nation has an
incredibly rich fossil legacy, but these are
nonrenewable resources, so we need to
be responsible stewards. No more T. rexes
are being made, and there are only so
MGIEKIJEYRE
Credit: lȶȉȦȍ)EZMH'IGOIV1EW:IKEW7IZMI[/SYVREP.RG
many out there beneath the ground, eroding at the surface, or in collections, so the
way that we manage them should be very
different from how we manage grizzly
bears and redwood trees and grasslands.
TC: In 1957, a fossil site in South
Dakota — Fossil Cycad National Monument — was abolished. What lessons
have we learned from that?
VS: It’s a very unfortunate story of
paleontological resource mismanagement. Cycads look sort of like pineapples
with beautiful fronds on top. The site in
the southern Black Hills preserved the
remains of very large cycads that existed
during the time of the dinosaurs. Paleobotanists were amazed by the quality of
the preservation; they could make thin
sections and observe cellular structure
and other features that had never before
been seen in the fossil record. But the park
service didn’t do much with the monument after it was established in 1922, and
visitors eventually pocketed so many of
the fossils that the site was completely
denuded. Without fossils there was no
longer a reason for the monument to
exist, so Congress voted to abolish it
in 1957. I think it is a compelling story
that sends a strong message about the
importance of responsible stewardship
of nonrenewable fossils.
TC: How did you learn about the former national monument?
VS: I first saw a reference to Fossil
Cycad when I was working at Badlands in the 1980s. I asked around, but
very few people knew about the site;
it seemed like it had been almost completely forgotten. I began to do some
research and over the last 35 years I’ve
accumulated quite a bit of historical
information. When I worked at Petrified Forest [National Park], one of
the issues I was trying to deal with was
illegal souvenir collecting of petrified
wood by park visitors. I began using the
Fossil Cycad story to demonstrate that
there are localities that have disappeared
because of uncontrolled collecting.
TEKIȍȴ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Down to Earth
Androcycas santuccii, a fossil cycad plant
discovered in the Upper Triassic Chinle
+SVQEXMSR MR &VM^SREƶW 5IXVMJMIH +SVIWX
National Park, was named in honor of San
tucci, the former park paleontologist who
drew researchers’ attention to the fossil.
It is the holotype specimen of both a new
species and a new genus and one of two
newly discovered fossil species that have
been named for Santucci.
Credit: NPS photo
TC: You began your career in the
field. How do you remain inspired
now that you’re in an administrative role?
VS: We have only scratched the surface in terms of what we know about the
history of life. From my 35 years of working in paleontology, I strongly believe
that most of what is to be learned about
the history of life is yet to be discovered.
For example, in 2012, the National Park
Service completed a 10-year inventory of
fossils throughout the entire park system.
Seventeen units were established to protect paleontology resources, but through
this inventory we identified 267 that
host pieces of our country’s paleontological heritage. Together, these tell quite a
comprehensive story of the evolution of
life over more than a billion years, from
the early Paleozoic marine invertebrates
of Death Valley National Park to the
Mesozoic dinosaurs of Dinosaur National
Monument to the ice-age fossils of Grand
Canyon National Park.
Santucci published Yellowstone National
Park’s first paleontological inventory in
Ȧȟȟȁ
Credit: Bianca Santucci
TC: Did you discover any new fossils
during the inventory?
VS: When we began to research the
Colonial National Historical Park near
Norfolk, Va., which includes the early
European settlement of Jamestown, park
officials didn’t think that there were any
fossils there. When we began to research
the area, we learned that many European
cartographers who mapped the surrounding shoreline in the 1600s were based
there and often earned additional money
by collecting curios and taking them back
to Europe to sell to private collectors.
Some of these ended up in European
museums, and one, a little bivalve pecten
specimen, was described in an article published in the late 1600s. Everyone seems
to agree that this is not only the first
fossil specimen from [land that would
become] a U.S. national park, but also the
first fossil from the Western Hemisphere
to be described and published. It was
formally named &KHVDSHFWHQ MHƛIHUVRQLXV
and is now Virginia’s state fossil. It’s a
really cool story.
TC: How did fossil discoveries play a
role in our country’s early history?
VS: Thomas Jefferson and some of
his contemporaries had a real fascination
with mammoths and mastodons; Jefferson had mammoth remains displayed in
the main den in his home at Monticello.
He was optimistic that Lewis and Clark
would encounter a live mammoth or
mastodon as they journeyed west for the
first time, and he instructed them to be
TEKIȍȏ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Down to Earth
ERXYGGMWXERHWMRJVSRXSJXLI/SLR;IWPI]5S[IPP+SWWMP8VEGO'PSGOHMWGSZIVIHMRȶȉȉȟMRXLI1S[IV/YVEWWMG3EZENSERHWXSRIMR
,PIR(ER]SR7IGVIEXMSR&VIE8LIXVEGO[E]TYWLIHFEGOXLIVIGSVHSJSVRMXLSTSHWMR3SVXL&QIVMGEF]ȶȉQMPPMSRXSȶȍQMPPMSR]IEVW
Credit: NPS photo
on the lookout. There are many other
examples as well. In Gettysburg, there’s
a stone bridge that was constructed near
the battlefield in the 1930s. During the
quarrying operation [to collect stone for
the bridge], workers discovered dinosaur
footprints from the Triassic in the stone.
So, long before Union and Confederate
soldiers marched across the battlefield at
Gettysburg, dinosaurs left their footprints
in the mud there.
TC: Since your time at Badlands, have
any new laws been passed to better
protect America’s fossil legacy?
VS: Badlands was a real center of activity because of how valuable these fossil
mammals were and how little preparation
they needed. The legal battle and eventual
sale of Sue the T. rex for $8.5 million in
1997 showed that there was a very strong
commercial market for fossils, and it
demonstrated the need for protective
legislation. It took a long time, but finally,
in 2009, President Obama signed the
Paleontological Resources Preservation
Act, which provides the same level of
protection for fossils that archaeological resources had been granted 30 years
earlier. I think it’s going to be a strong
deterrent and has already shifted more
commercial fossil collecting to private lands.
TC: Which one would you say is your
favorite national park?
VS: I would have to say Yellowstone.
When I first visited that park on that
same cross-country trip at 13, I remember going in with a lot of excitement and
expectation and departing with a tear in
my eye because I didn’t want to leave. It’s
a very special place, and the fact that I was
hired to work there 20 years later was
the thrill of a lifetime. I never imagined
that could happen, and that experience
profoundly influenced the way that I
think and what I share with and teach
my children. I’m very proud that during
my time there I published the park’s first
paleontological inventory. Being part of
Yellowstone’s history is very fulfilling for
me, and I’m honored to have contributed
in that way.
A geologist by training, Cook is a freelance
science and travel writer and EARTH rov
ing correspondent based in Boulder, Colo.
Follow her at [[[HS[RȶIEVXLWGMIRGIGSQ
and @GeoTravelTerri.
TEKIȍȍ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Benchmarks
2E]ȴȶȉȉȴ
New Hampshire’s Old Man of the Mountain Falls
Rachel Crowell
O
n May 2, 2003, the Old Man
of the Mountain, New Hampshire’s famous face-shaped
granite formation, adorned
the side of Cannon Mountain in Franconia Notch State Park, just as it had for
millennia. But by the next morning, it was
gone: The iconic stone face had fallen.
Even before the formation toppled,
many knew that the state emblem, also
known as the Profile or the Great Stone
Face, would eventually collapse. The
blocky outcrop of Jurassic-aged Conway
Granite — measuring 13.7 meters tall by
9.1 meters wide and weighing 6,530 metric tons — was perched 370 meters high
on a mountainside in a climate where
freeze-thaw erosion is common. Still, the
news of the Old Man’s collapse came as a
shock, even to New Hampshire geologists.
David Wunsch, New Hampshire’s
state geologist and director of the New
Hampshire Geological Survey at the time,
was at home when his phone rang on
May 3, 2003. When he saw the call was
coming from CBS News, he thought,
“Hmm, that’s not good,” he says.
Brian Fowler, an engineering geologist with a long history with the Old
Man, also heard about the fall via a phone
call: On May 3, Fowler was working in
his office when he received a call from a
reporter with Manchester’s Union Leader
newspaper asking him for his reaction to
the collapse, a call he initially thought was
a prank. Once he realized it wasn’t, he was
“stunned by the news,” he says.
Soon after hearing the news, Wunsch,
who is now Delaware state geologist
and director of the Delaware Geological
Survey, called Fowler to coordinate an
immediate trip to survey the damage.
Details of the collapse soon emerged. The
Great Stone Face was intact when state
park employees left work on the evening
of May 2, Fowler says. Campers who slept
in the state park reported hearing loud
noises during that “wet, windy night,”
but “the collapse wasn’t identified until
about 10:30 the next morning.”
Fowler was returning to familiar
ground. He had first evaluated the rock
mechanics of the Old Man in 1976 while
working for the New Hampshire Department of Transportation (NHDOT). He
was tasked with determining whether an
interstate highway could be built through
3I[-EQTWLMVIƶWJEQIHJEGIWLETIHSYX
crop of Conway Granite, known as the Old
2ERSJXLI2SYRXEMRWLS[RMR&TVMPȶȉȉȴ
It collapsed one month later.
Credit: Jeffrey Joseph, public domain
Franconia Notch without endangering
the Old Man. And in the years since, he
had worked with the state on preservation efforts. Now, rather than making
plans to preserve the Old Man, the goal
shifted to deciding how to memorialize it.
Preserving an Icon
The realization that, from certain
angles, the granite outcrop resembled
the profile of a man was first noted by
Francis Whitcomb and Luke Brooks in
1805 while they were on a crew surveying Franconia Notch. In 1832, Nathaniel
Hawthorne visited the
profile, and in 1850
he published “The
Great Stone Face,” a
short story inspired
by the Old Man.
By the mid-20th
century, the formation had become a
popular tourist destination, and an icon
After the collapse, some wanted the icon to be rebuilt, but a state committee decided that rebuilding was not feasible. Instead, a
PIKEG]JYRH[EWIWXEFPMWLIHXSFYMPHEQIQSVMEPTPE^EMR+VERGSRME3SXGLXEXI5EVO
Credit: both: Old Man of the Mountain Legacy Fund
TEKIȍȰ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Benchmarks
of the state. In 1945, the New Hampshire
legislature adopted a state emblem and
motto: the likeness of the Old Man surrounded by the phrase Live Free or Die.
But as early as 1872 — when the Appalachian Mountain Club and a Boston
newspaper collaborated on a comprehensive article about the Old Man, which
included a discussion of its apparently
delicate structure — there were concerns
about its eventual collapse, according to a
2005 paper by Fowler in the journal Environmental and Engineering Geoscience.
Over the years, many efforts were
made to prevent the collapse of the Old
Man so that it would live on as a geologic wonder and state symbol, as well
as a tourist attraction. Experts and laypeople wanted to preserve the profile,
but many also feared that undertaking
a major effort to bolster the formation
might inadvertently disturb its precariously cantilevered position on the side
of Cannon Mountain, causing it to meet
an early end.
In 1915, Guy Roberts, a Whitefield,
N.H., reverend, persuaded granite quarryman E.H. Geddes to take on the task of
“securing the rock mass,” Fowler noted
in his paper. The project was approved
by local officials, but funded by Roberts
and Geddes. The next year, Geddes put
the plan into action. By hand, he drilled
and installed tie rods into the Great Stone
Face’s forehead slab. These rods were
placed to maintain the “center of gravity
relationships” between different slabs
within the profile. Remarkably, the rods
remained in place until the Old Man fell.
In 1937, Geddes returned to the Old
Man to check on his previous work
and “install several additional tie rods,
seal over several cracks where water
… [seeped] between the slabs and add
several poured-in-place cement blocks
to provide baselines for detection of
incipient movement between the slabs,”
Fowler wrote.
The next hardware added to the profile
was a collection of turnbuckles installed
in 1958 using mechanical drilling equipment. These were added “between the
two largest pieces of the forehead slab, to
8LIQIQSVMEPTPE^EMRGPYHIW
“profilers” that recreate the
image of the Old Man in its
former location on the side
of Cannon Mountain.
Credit: both: Old Man of the
Mountain Legacy Fund
keep the front portion, with its perched
crest block, from sliding off the profile,”
according to Fowler. Geotechnical monitoring of the Old Man also began with
the installation of the turnbuckles, as they
were outfitted with strain gauges.
At this stage, however, the preservation attempts were already met with
skepticism, wrote historian Frances Ann
Johnson Hancock in her 1983 book, “Saving the Great Stone Face: The Chronicle
of the Old Man of the Mountain.”
“One newspaper remarked negatively,”
Hancock wrote: “‘The rugged profile in
Franconia Notch is in danger of coming
apart at the seams. If it does, it will come
roaring down from the mountain in a
1,200-foot landslide, and all the king’s
horses and all the king’s men will never
be able to put this Humpty Dumpty
back together again.’ Some engineers
feared that the work ‘might trigger a
sizeable collapse’; others declared that
efforts could, at best, ‘be expected to only
prolong the life of the Old Man’ whose
destruction, they said, would ‘ultimately
be inevitable.’”
An Interstate Through
the Notch
Not only was the Old Man still vulnerable, but the quest for answers about
the stability of the formation was also
incomplete. NHDOT needed to know if
an interstate could be built beneath the
profile and, if construction proceeded,
what steps could be taken to keep the
profile safe.
In 1976, Fowler was a 25-year-old
early-career geologist when, along with
civil engineer Roger
Martin, he was tasked
with making this determination. “I was told
to get up there and get
going,” he says. Unlike
many others, he didn’t
fret about the possibility
of accidentally knocking
down the Great Stone
Face as he conducted
the first structural-mechanical analysis of the formation.
“I think I was too young to understand
the risk we faced,” he says. He didn’t
realize how much his reputation might
have been damaged if the Great Stone
Face — which rested almost entirely on
the chin block, 80 percent of which was
cantilevered out over the edge of the
cliff — had fallen on his watch. His lack
of concern “was kind of a mixed blessing,”
he says. A lifelong rock climber, he was
just thrilled to be “getting paid to rock
climb all summer.”
Fortunately, he and Martin were able
to use rock climbing techniques, modern
for the time, to safely climb down the Old
Man’s face. Using photogrammetry, they
determined that highway construction
could proceed without harming the Old
Man, if vibrations from blasting were
kept to a minimum near the profile. By
1986, the interstate was completed without damage to the Old Man.
The Old Man’s Tumble
“It was a pretty clear May day when the
Old Man was discovered fallen,” Wunsch
says. The road to the site where the Old
Man once perched was closed by a state
trooper. “I pulled over to one of the viewing spots and looked up, just to see how
much of the Old Man did indeed fall. I
could only see the straggly remains of the
steel turnbuckles,” he says.
TEKIȍȮ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
Benchmarks
The annotated photo at left shows the
line along which the outcrop that had
formed the Old Man of the Mountain
failed. The photo at right shows the
remaining surface with blocks labeled.
Credit: left: K. Cantner, AGI, after Fowler,
Environmental and Engineering Geoscience,
ȶȉȉȍ VMKLX9RMSR1IEHIV(SVTȶȉȉȴ
“The intricate profile resulted from
chemical weathering and freeze-thaw
rockfalls from the glacially eroded face of
Profile Mountain,” Wunsch and Fowler
noted in a 2004 Geotimes article. “These
same processes were also responsible for
its ultimate demise,” they added.
Demise might be an unusual way to
describe an erosional process, but the
formation was much more than a cluster of rocks to many New Hampshire
residents. “The oldest member of my
family just died,” a tearful David Nielsen
said in the aftermath of the collapse.
David’s father, Niels Nielsen, began
maintaining the outcrop in 1958 when
he was a bridge engineer for NHDOT.
In 1980, David began
helping his father, who, 10 years later,
was appointed by the governor as the
first official caretaker of the Old Man,
a role David later also held. Year after
year, Niels and other family members
had returned to repair an epoxy seal that
Niels originally placed in 1972 to prevent
cracks caused by freeze-thaw cycles from
destabilizing the Old Man.
While the scene of the fallen Old Man
brought Fowler to tears on his drive
home that day, understanding how
the formation failed helped him finally
answer a long-held question: Was there
anything more he could have done to
prevent its ultimate failure? In his analysis that preceded the construction of the
interstate through Franconia Notch, he
had not been able to use a technique
that was in its infancy in the
1970s: finite element analysis. He had long wondered
whether the technique
might have offered
insight that would
have helped to preserve the Old Man.
“In retrospect, now
that we know the
mechanics of how
it failed, we pretty
The Old Man of the
well know there wasn’t much that could
have been done” at the time to prevent
the failure, he says.
The Old Man’s Legacy
“Had the Old Man been able to survive another decade or so,” Wunsch
notes, it might have been possible to
use lidar-based techniques to try to save
the formation. A lidar map could have
made it possible to fit the profile with
an unobtrusive metal mask bolted to
the surrounding rock, he adds. Wunsch
was a technical consultant for the Old
Man Restoration Task Force, the governor-appointed body charged with
determining how to memorialize the Old
Man. Although some wanted to rebuild
the natural wonder, arguments against it
included the instability of the remaining
rock mass, the risk to restorers and the
potential for environmental damage.
The task force disbanded and the Old
Man of the Mountain Legacy Fund, of
which Fowler is now president, took
over the project of memorializing the
Old Man. Today, visitors are greeted
by a plaza, where, by looking through a
profiler suited to their height, they can
experience an optical illusion that the Old
Man is back on the mountain, where it
had long stood the test of time.
Mountain continues to
be featured on the New
Crowell, a former AAAS Mass Media Fel
Hampshire state quarter,
PS[ MW E 2MH[IWXFEWIH QEXL ERH WGM
[LMGL[EWJMVWXMWWYIHMRȶȉȉȉ
Credit: public domain
ence freelance writer. Follow Crowell
@writesRCrowell.
TEKIȍȁ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
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Geologic Column
A World Without Measure
John Copeland
H
ave you ever stopped to consider how difficult our lives
would be without uniform
systems of measurement?
Imagine going to the gas station to fill
up your vehicle and trying to figure out
the volume of gas you’re actually getting.
Or buying produce and being unsure if
you’re paying the same price per weight
as other shoppers. Or having laser eye
surgery to correct your vision without
knowing whether the laser’s power is
accurately known. Whether you use
English measurements — the convention
in the U.S. — or metric like most of the
rest of the world, you’re using a uniform
system, and it’s possible to easily translate
between one system and another. But it
wasn’t always like that.
Today, we honor the
treaty...by celebrating
World Metrology Day on
2E]ȶȉ
Ancient measurements of length were
based on the human body: the length of
a foot, the length of a stride or the span
of a hand, for example — all of which are
variable units.
About 3000 B.C., a pharaoh established the Egyptian cubit, decreeing it to
be the length from the tip of his middle
finger to his elbow. Since different people have different lengths of arm, the
Egyptians developed a standard royal
cubit preserved in the form of a black
granite rod. Workers at building sites
were given copies in granite or wood, and
it was the responsibility of the architects
to maintain them. About 1700 B.C., the
Babylonians developed their own basic
unit of length also called the cubit, which
was slightly longer than the Egyptian
cubit. The Greeks used the width of a
finger as their basic unit of length. The was the establishment of the InternaRomans used the foot, which was divided tional Bureau of Weights and Measures,
into 12 inches, as their basic unit. Longer housed in Paris, and the Convention
measurements were derived from sol- of the Meter of 1875, also known as
diers on the march. Five feet equaled one the Meter Treaty, which was signed
pace, and 1,000 paces measured a Roman on May 20, 1875, by representatives of
mile, which is reasonably close to the 17 nations, including the United States.
More countries signed on in the years
American mile used today.
As the Roman Empire spread, its mea- that followed.
surement system was adopted throughout
Today, we honor the treaty that estabmuch of Europe. The only problem with lished the first uniform, worldwide system
invaders dictating standards of measure of measurement by celebrating World
was that many places were repeatedly Metrology Day on May 20. Metrology is
invaded by one group and then another, the science of measurement, and it plays
each of which brought their own stan- a central role in scientific discovery and
dard units of measure. In England, for innovation, industrial manufacturing,
example, Anglos, Saxons, Jutes and Danes international trade, and our daily lives.
Today, only the United States, Libebrought measures such as the perch, the
rod, the furlong and the fathom. Finally, ria and Myanmar do not use the metric
in the early 13th century, England issued a system as the predominant system of
royal ordinance called “Assize of Weights measurement. However, as metric is the
and Measures” that defined a long list of sole measurement language of most of the
measurements to be used across the land. world, foreign customers buying AmeriIt was an extremely successful attempt at can products are gradually requiring that
standardization; its definitions lasted for such products be labeled and produced in
nearly 600 years.
metric units; eventually, the United States
In France, there was no standardiza- may finally become a metric nation.
tion until the French Revolution. In 1798,
Making quality-assured measurethe National Assembly adopted a proposal ments is an expertise in its own right,
that a new measurement system be based and must be carried out in ways such that
on a length from nature, and should have everyone can have full confidence in the
decimal subdivisions. All measures of results. This May 20, I suggest stopping
area, volume, weight and so on were to be to appreciate the many decisions in your
linked to this fundamental unit of length. life that are based on uniform and accurate measurements.
This was the meter.
The proposal was designed to create
an international system of measurement. Copeland is a filmmaker in California who
However, continued tumult in France has produced television programs rang
prevented this from happenMRK JVSQ Ƹ'EF]PSR ȍƹ XS Ƹ+EGIW
ing until decades later. In the
of Earth” (produced with the
1870s, scientists from around
American Geosciences Institute).
the world were invited to a
Copeland also works with MIT’s
conference in Paris, the aim of
*\TIVMQIRXEP XYH] ,VSYT XS
which was to improve internainstruct undergraduate science
and engineering students in the
tional scientific cooperation by
art of visual communication and
applying the metric system as
the worldwide standard. The
WXSV]XIPPMRK8LIZMI[WI\TVIWWIH
outcome of the conference Credit: Fran LoCascio EVIcLMWS[R
TEKIȰȏ•2E]ȶȉȦȁ• EARTH •[[[IEVXLQEKE^MRISVK
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