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Icarus 306 (2018) 122–138
Contents lists available at ScienceDirect
Icarus
journal homepage: www.elsevier.com/locate/icarus
Evidence for triple-junction rifting focussed on local magmatic centres
along Parga Chasma, Venus
J.R. Graff a,∗, R.E. Ernst a,b, C. Samson a,c
a
Department of Earth Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
Faculty of Geology and Geography, Tomsk State University, 36 Lenin Avenue, Tomsk 634050, Russia
c
Department of Construction Engineering, École de Technologie Supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada
b
a r t i c l e
i n f o
Article history:
Received 10 May 2017
Revised 29 January 2018
Accepted 2 February 2018
Available online 7 February 2018
a b s t r a c t
Parga Chasma is a discontinuous rift system marking the southern boundary of the Beta-Atla-Themis
(BAT) region on Venus. Along a 1500 km section of Parga Chasma, detailed mapping of Magellan Synthetic
Aperture Radar images has revealed 5 coronae, 11 local rift zones distinct from a regional extension pattern, and 47 graben-fissure systems with radiating (28), linear (12) and circumferential (7) geometries.
The magmatic centres of these graben-fissure systems typically coincide with coronae or large volcanoes,
although a few lack any central magmatic or tectonic feature (i.e. are cryptic). Some of the magmatic
centres are interpreted as the foci of triple-junction rifting that form the 11 local rift zones. Cross-cutting
relationships between graben-fissure systems and local rift faults reveal synchronous formation, implying
a genetic association. Additionally, cross-cutting relationships show that local rifting events postdate the
regional extension along Parga Chasma, further indicating multiple stages of rifting. Evidence for multiple
centres of younger magmatism and local rifting against a background of regional extension provides an
explanation for the discontinuous morphology of Parga Chasma. Examination of the Atlantic Rift System
(prior to ocean opening) on Earth provides an analogue to the rift morphologies observed on Venus.
© 2018 Elsevier Inc. All rights reserved.
1. Introduction
Venus and Earth are sister planets due to their similarities in
bulk composition and physical properties, however, they are very
different from a geological perspective (Phillips and Hansen, 1994;
Donahue and Russel, 1997; Chaisson and McMillan, 2010; Head,
2014; Taylor, 2014). A new view of Venus was unveiled in the early
1990s when NASA’s Magellan spacecraft obtained high resolution
(75–100 m/pixel) images for 98% of Venus’ surface using Synthetic
Aperture Radar (SAR) (Young, 1990; Saunders et al., 1990, 1992;
Saunders and Pettengill, 1991). Magellan SAR images have since
provided planetary scientists with detailed information regarding
Venus’ surface geology and have primarily been used to identify
and catalogue tectono-magmatic structures and stratigraphic units
(e.g. Saunders et al., 1992; Phillips and Hansen, 1994; Ivanov and
Head, 2011, 2013). All basemap SAR and altimetry images presented herein were obtained during the Magellan mission and
were compiled by the U.S. Geological Survey (USGS) Astrogeology
Science Center (http://astrogeology.usgs.gov/).
∗
Corresponding author.
E-mail
addresses:
jamie.graff@carleton.ca
(J.R.
Graff),
richard.ernst@
ernstgeosciences.com (R.E. Ernst), claire.samson@carleton.ca (C. Samson).
https://doi.org/10.1016/j.icarus.2018.02.010
0019-1035/© 2018 Elsevier Inc. All rights reserved.
Contrary to Earth, plate tectonics is thought not to be currently active on Venus due to a lack of observable plate boundaries
(e.g. Phillips and Hansen, 1994). Instead, Venus is suggested to
be operating predominantly in a single plate, stagnant lid regime,
with all magmatism occurring in intraplate settings (Head et al.,
1992; Grosfils and Head, 1994a,b; Solomatov and Moresi, 1996;
Nimmo and McKenzie, 1998; Crumpler and Aubele, 20 0 0; Ernst
and Desnoyers, 2004; Hansen and Young, 2007). Despite the lack
of plate tectonics, however, Venus does experience major rifting.
Rift systems are present in numerous regions of the planet, such
as the Diana/Dali Chasma (Hansen and DeShon, 2003) and the Ganis Chasma (Brakenridge et al., 20 0 0) located to the southwest
and northwest of the Atla Regio volcanic rise, respectively. They
are most dramatically present, however, throughout the BAT region (Fig. 1) where they enclose a triangular region. The ENE-WSW
trending Hecate Chasma system is 80 0 0 km long and connects Atla
and Beta Regiones (Hamilton and Stofan, 1996). The NW-SE trending Parga Chasma system is 10,0 0 0 km long and connects Atla and
Themis Regiones (Martin and Stofan, 2004; Martin et al., 2007).
The N-S trending Devana Chasma system is 30 0 0 km long and connects Beta and Phoebe Regiones (Kiefer and Swafford, 2006), terminating a few hundreds of kilometres north of Themis Regio. Associated with these rifts are numerous coronae and volcanic cen-
J.R. Graff et al. / Icarus 306 (2018) 122–138
123
Fig. 1. Sinusoidal projection of the entirety of Venus’ surface (central meridian at 180°E) showing major structures, including rift zones, large volcanoes, and coronae. The
area confined by the Beta-Atla-Themis (BAT) region is outlined by dashed lines; the location of the study area is indicated by the black square. Modified from Fig. 2 in
Herrick (1999). All subsequent Venus maps in this paper are also in a sinusoidal projection with a central meridian of 180 E.
tres (Senske et al., 1992; Stofan et al., 1995; Martin et al., 2007).
There are also graben-fissure systems radiating away from some
of these tectono-magmatic centres (e.g. Grosfils and Head, 1994a;
Ernst et al., 2003).
It has been observed that many of the large volcanoes and coronae of the BAT region are often at the centre of triple-junction
rifting (cf. Burke and Dewey, 1973; Torske, 1975) and have associated topographic and geoid highs. This has been interpreted to
indicate that an underlying mantle plume caused domal uplift, radiating arms of triple-junction rifting (Senske et al., 1992; Smrekar et al., 1997; Herrick, 1999), and radiating graben-fissure systems (i.e. dyke swarms) (e.g. Grosfils and Head, 1994a; Ernst et al.,
2003), in addition to the voluminous magmatism of the individual volcanic edifices (Senske et al., 1992). As long recognized, the
rift systems in the BAT region represent attempted breakup but did
not reach the stage of ocean opening (e.g. Head et al., 1992; Airey
et al., 2017 and references therein).
On Earth, rifting commonly occurs near volcanic centres of large
igneous provinces and forms a series of fractures surrounding a
spreading volcanic edifice, or on a larger scale, associated with
triple-junction rifting about mantle plume centres and associated
large igneous provinces (Turcotte, 1995; Hazlett and Hyndman,
1996; Şengör, 2001; Şengör and Natal’in, 2001; Ernst, 2014). It has
been inferred that the Venusian rift systems of the BAT region are,
in a similar fashion, due to triple-junction rifting about the main
volcanic centres located at the ends of the rift systems (cf. Stofan
et al., 1995; Hamilton and Stofan, 1996; Herrick, 1999). However,
there are considerable complexities in the pattern observed along
the rift systems. In particular, as shown in this paper (based on
rift segments extracted from the rift map of Graff et al., (2015)),
the Parga Chasma rift system consists of 45 local segments rather
than one continuous rift segment. Hecate Chasma consists of 13 local segments. Devana Chasma, however, only consists of two main
segments, representing a fairly continuous rift system.
An outstanding question related to rifting processes on Venus
is the origin of the discontinuous rift pattern observed along Parga
and Hecate Chasmata. Another question is the relationship of the
coronae, volcanoes, and radiating graben-fissure systems to the rift
zones, both in terms of timing and genesis. Previous workers, such
as Martin et al. (2007), provided an exhaustive study examining
the spatial and genetic relationships of the coronae in the Parga
Chasma region. Their study examined multiple characteristics of
coronae, including topographic signatures and associated volcanism, located both in proximity to and away from the main rift
branches of Parga Chasma. It revealed that coronae have roughly
equal distributions both proximal and distal to the rift, and that
any causal link between coronae and rift formation remained inconclusive.
2. Research objectives
The overarching goal of this study is to identify and map the
extensional lineaments associated with major graben-fissure systems and rift zones in the BAT region. Specific objectives are: (1) to
resolve the relative chronology of tectono-magmatic events along
a section of the Parga Chasma rift system; (2) to characterize the
morphological differences between local and regional rifting along
Venusian rift systems; and (3) to unravel the potential genetic association between local rift zones and individual magmatic centres.
To achieve the first objective, a detailed study area (1.2 Mkm2 )
has been selected in the southeast portion of the BAT region,
within the coordinates of 260–275°E and 25–33°S (Fig. 1). The
study area includes a complex 1500 km section of the Parga
Chasma rift system and is host to a wide variety of tectonomagmatic structures, including graben-fissure systems, local rift
zones, regional extension features, coronae, and large volcanoes.
The following activities were performed:
(1) Detailed mapping of the radar-bright lineaments representing individual graben-fissures, and grouping graben-fissures
into separate systems of different geometries.
(2) Mapping of extensional lineaments interpreted to represent
both local and regional rift faults of Parga Chasma.
124
J.R. Graff et al. / Icarus 306 (2018) 122–138
(3) Interpreting cross-cutting relationships between grabenfissure systems and rift faults to produce a relative chronology of events in the study area using the regional rifting
along Parga Chasma as a baseline.
Since graben-fissure systems are generally thought to overlie
dykes (e.g. Grosfils and Head, 1994a,b; Ernst et al., 2001; Studd
et al., 2011), the final map of the study area will additionally become part of the Venus global dyke swarm map (Ernst et al., 2009;
Studd et al., 2010a,b,c,2011).
The second objective aims to characterize the difference in morphology observed among the three major rift systems of the BAT
region. Most notably, Parga Chasma exhibits a significantly more
discontinuous morphology than either Hecate or Devana Chasmata, and contains an abundance of coronae within close proximity (<∼50 km) to several local rift segments.
The detailed mapping and observations gathered to tackle objectives 1 and 2 form the basis for addressing the third objective and to test the hypothesis that the mapped section of
Parga Chasma predominantly developed as a series of local triplejunction rifting events extending from individual magmatic centres. This model is then applied on a regional scale to interpret the
rift segmentation extracted from the BAT rift map of Graff et al.
(2015) for Parga Chasma as a whole and also for Hecate Chasma.
The Atlantic Rift System (prior to ocean opening) is invoked as a
terrestrial analogue to Venusian rift morphology.
along steep slopes except perhaps for those dyke swarms associated with rift zones. Rift zones are composed of many broad
and densely-packed extensional structures, and commonly overprint underlying unit morphologies (Ivanov and Head, 2011, 2013).
On SAR images, extensional features which are grouped as sets of
semi-parallel, quasi-linear radar-bright lineaments, and which align
along flanks of topographic troughs are typically interpreted to be
rift faults (Stofan et al., 20 0 0; Martin et al., 20 07; Graff et al., 2015;
Graff, 2016). The floors of these topographic troughs are often covered by lava flows, while the exterior walls of the central valley
tends to be elevated relative to the surrounding plains, representing rift flank uplift (Mark et al., 2014).
Quantitative criteria such as lineament thickness and sinuosity were also used to distinguish graben-fissures from rift faults
(Graff et al., 2015). Lineament thickness represents the magnitude
of the exposed offset of either a rift fault or graben-fissure wall.
Sinuosity captures the departure from a linear trend and is calculated by taking the ratio of total length measured along the lineament over its end-to-end length. In general, rift faults (as identified by their association with topographic troughs) exhibit both
larger thickness and sinuosity than graben-fissures as shown in
a comparative study of radar images from Venusian and terrestrial rift settings by Graff et al. (2015). On Venus, rift faults and
graben-fissures exhibit average thicknesses of 896 ± 263 m and
361 ± 101 m, respectively. The average sinuosity for Venusian rift
faults and graben-fissures are 1.057 ± 0.032 and 1.015 ± 0.009, respectively.
3. Mapping methodology
3.1. Data source and study area
This research primarily utilizes Magellan SAR images (75–
100 m/pixel) imported into ArcGIS 10.3. All images displayed
herein were projected using the GCS Venus coordinate system (cf.
Davies et al., 1992). SAR images are greyscale images where pixel
brightness indicates the intensity of radar signal return, due to either surface roughness or the orientation of a structure relative to
the incident radar pulse. The Magellan mission also obtained measurements of Venus’ surface elevation using radar altimetry, which
were compiled into both topography and metre scale slope images
at a lower resolution of 3–5 km/pixel.
The study area covers parts of the Helen Planitia (V-52) and
Themis Regio (V-53) quadrangles, and comprises a 1500 km portion of the Parga Chasma rift system. Within the study area, there
are 5 coronae as catalogued by the International Astronomical
Union (IAU), 11 local rift zones of Parga Chasma, and 47 grabenfissure systems, exhibiting radiating, linear, and circumferential geometries.
3.2. Distinction between graben-fissures and rift faults
A challenging aspect of this research involves the identification
and detailed mapping of both graben-fissures and rift faults, as
well as the distinction between the two types of extensional features. On SAR images both graben-fissures and rift faults are radarbright extensional lineaments with similar morphological characteristics. The following criteria assisted in making the distinction
between the two features: geometric patterns and their relationship with topography, lineament thickness, and sinuosity.
Qualitatively, graben-fissures are grouped into separate systems
with specific geometric patterns—radial, linear, or circumferential—
that reflect the propagation of underlying dyke swarms, and are
often found in spatial association with magmatic centres (e.g.
Grosfils and Head, 1994a,b; Ernst et al., 20 01, 20 03; Ernst and
Buchan, 2001). Graben-fissure systems are not typically aligned
3.3. Cross-cutting relationships
The relative chronology of tectono-magmatic events mapped
within the study area was determined by the analysis of crosscutting relationships between interacting graben-fissures and rift
faults. Types of cross-cutting relationships that were most often
observed included: (1) cross-cutting relationships between the lineaments of separate graben-fissure systems; (2) cross-cutting relationships between graben-fissures interacting with local rift zones
and the regional rifting pattern along Parga Chasma; and (3) the
effect of young lava flows obscuring (or partially obscuring) the
trace of both graben-fissures and/or rift faults (Fig. 2). Crosscutting between interacting graben-fissures and rift faults is observed in both direct and indirect ways. Direct interactions result
when the lineaments from graben-fissure systems or rift faults are
observed to be physically cross-cutting the lineaments belonging
to other structures/events (i.e. younger lineaments directly overprinting older lineaments).In such cases, younger lineaments can
often be seen as creating disturbances or discontinuities in the
trend of older lineaments. Indirect interactions result when the
lineaments from separate graben-fissure systems are observed to
interact with a mutual geologic feature (e.g. a lava flow), but not
directly with each other. In addition, contrasts in radar backscatter intensity were sometimes observed when younger features partially or completely truncate the propagation of older systems.
The relative chronology of events in the study area was developed by comparing the timing of graben-fissure system emplacement relative to local and regional rifting along Parga Chasma.
Graben-fissures that overprint rift faults are interpreted to have
been emplaced after rifting, whereas graben-fissures that are overprinted by rift faults are interpreted to have been emplaced prior
to rifting. When there is ambiguity between interacting grabenfissures and/or rift faults, synchronous emplacement is interpreted
to have occurred. Age relationships were further constrained when
the presence of lava flooding obscured the radar signal of grabenfissures and/or rift faults.
J.R. Graff et al. / Icarus 306 (2018) 122–138
125
Fig. 2. Characteristic traits observed when examining cross-cutting relationships. (Top) Trend of older E–W trending graben-fissures offset by the emplacement of younger
NW–SE rift faults; (bottom) older E–W trending graben-fissures completely truncated by a young lava flow, with E–W trending rift faults extending across the flow, but
still partially obscured, and therefore interpreted as older than the flow. (a) and (c) simplified schematics with older lineaments in grey, younger lineaments in black, and a
young lava flow as a grey-filled polygon. (b) and (d) representative SAR images similar to schematics. The location of part b is ∼266 E, 26 S, and for part d is ∼266 E, 29 S.
North is approximately up on parts b and d.
4. Detailed mapping of graben-fissure systems and rift zones
5. Tectono-magmatic history
4.1. Overview
Following the approach of Studd et al. (2011) and using the
relative age relationships developed in Supplementary File 1, a
relative chronology of the tectono-magmatic events within the
study area has been created. The age relationships between interacting radiating and linear graben-fissure systems and/or the local/regional rifting of Parga Chasma have been integrated into a
common timeline (Fig. 6). This approach (cf. Studd et al., 2011) assumes that the duration of emplacement for each graben-fissure
system was short (∼ a few Myr), based on terrestrial studies of
dyke swarm emplacement (e.g. Ernst et al., 2001; Ernst, 2014).
The initial regional extension and rifting of Parga Chasma is also
hypothesized to have occurred as a singular event over a relatively short time span of 10–50 Myr, based on the terrestrial rift
review and catalogue of Şengör and Natal’in (2001), and is placed
in the centre of the timeline. This estimate of rifting duration along
Parga Chasma, however, should be considered provisional pending
more research on the similarities and differences between rifting
on Venus and Earth. Local triple-junction rifting events have variable timing and, based on cross-cutting relationships, are genetically linked to the individual magmatic centres from which they
are focussed on.
In the timeline, horizontal lines are used to schematically represent the range of possible ages of formation of each system,
with ages decreasing (becoming younger) towards the right. When
graben-fissures interacted with regional rift faults from Parga
Chasma, the age relationships relative to this rifting could be determined and the system was provisionally placed on the left, centre,
or right side of the timeline. When the graben-fissures from different systems were observed to intersect, their age relationships
could be obtained and the position of these systems on the timeline was refined.
Examination of the 40 systems displayed on the timeline (Fig.
6) reveals that 17 (42.5%) predate regional rifting, 13 (32.5%) exhibit synchroneity with regional rifting; and 10 (25%) postdate regional rifting. Of the 13 systems synchronous with regional rifting,
Within the study area extensional lineaments interpreted
to represent graben-fissures and rift faults were systematically
mapped. The tally of mapped features includes a total of ∼12,600
extensional lineaments, with ∼11,0 0 0 belonging to graben-fissures
and ∼1600 belonging to rift faults. The graben-fissure lineaments
were further grouped into 47 separate graben-fissure systems and
catalogued as 28 radiating, 12 linear, and 7 circumferential systems
(Fig. 3; Tables 1–3). Over 10,0 0 0 graben-fissures were assigned to
the 47 grouped systems, while the remaining ∼10 0 0 mapped lineaments consist of isolated and/or unassigned sets of graben, fissures, or fractures. These unassigned lineaments may belong to
unidentified graben-fissure systems or unrecognized distal portions
to the aforementioned catalogued systems (cf. Ernst et al., 2003).
Within the study area over 1600 rift-related lineaments were
systematically mapped, corresponding to 633 regional rift faults
and 1016 local rift faults (Fig. 4). Regional rift faults have a NW–
SE orientation (catalogued as RF01) and are associated with the
overall regional NE–SW extension of Parga Chasma. The majority
of regional rift faults coincide with features previously mapped by
López and Hansen (2008), who catalogued them as regional fractures. Local rift faults are distinguished from regional rift faults
when they are found in association with individual magmatic centres. In the study area, 11 local sets of rift faults are identified (catalogued as RF02–RF12) and are often found in association with topographic troughs.
4.2. Relationships between graben-fissure and rift fault systems
Details on the cross-cutting relationships between interacting
systems and associated magmatic centres are provided in Supplementary File 1. Five examples are discussed (Fig. 5) that feature
major graben-fissure systems and magmatic centres that are interpreted as the foci of local triple-junction rifting.
126
J.R. Graff et al. / Icarus 306 (2018) 122–138
Table 1
Characteristics of the radiating graben-fissure systems in the study area.
System
Longitude
(°E)
Latitude
(°S)
Max
radius
(km)
Arc (°)
Number of
mapped
lineaments
Centre
elevation
(km)
Elevation
above MPR
(km)
Centre
within
corona?
R01
R02
R03
R04
R05
R06
R07
R08
R09
R10
R11
R12
R13
R14
R15
R16
R17
R18
R19
R20
R21
R22
R23
R24
R25
R26
R27
R28
269.75
267.50
275.75
273.00
262.00
262.50
268.00
269.50
272.25
272.00
268.25
261.75
262.50
271.25
268.25
265.50
266.00
275.75
269.50
273.25
269.50
263.00
268.00
267.00
267.75
266.25
266.75
267.00
28.00
27.50
31.75
27.25
28.00
27.50
30.50
30.75
27.25
32.00
30.75
27.50
28.00
28.00
30.50
28.25
24.50
31.50
29.00
27.25
29.75
28.00
23.00
30.00
31.50
27.00
29.00
23.00
747
560
475
471
448
352
280
232
230
226
221
213
203
203
197
196
186
175
154
152
148
114
111
107
99
99
57
46
360
210
190
320
50/45
250
335
60
75
40
95
50
90
65/10/5
60
85/70/25
330
80
55
85
60
65
60/35
90
60
35
40
70
733
763
700
634
344
711
834
218
162
117
237
136
172
112
106
309
391
302
122
75
132
63
110
74
104
85
38
38
6052.9
6051.8
6052.5
6053.2
6052.5
6052.2
6051.7
6052.2
6052.5
6052.1
6052.3
6052.8
6052.5
6053.6
6052.3
6052.4
6051.7
6052.6
6051.9
6053.2
6052.2
6052.3
6051.7
6052.8
6051.7
6051.5
6051.9
6051.9
1.9
0.8
1.5
2.2
1.5
1.2
0.7
1.2
1.5
1.1
1.3
1.8
1.5
2.6
1.3
1.4
0.7
1.6
0.9
2.2
1.2
1.3
0.7
1.8
0.7
0.5
0.9
0.9
Y
N
Y
N
Y
Y
N
N
N
N
N
Y
Y
N
N
N
Y
Y
N
N
N
Y
N
N
N
N
N
N
Associated
structure
Xmukane Corona
Obiemi Corona
Ts’an Nu Mons
Kulimina Corona
Kulimina Corona
Kulimina Corona
Kulimina Corona
Chuku Corona
Obiemi Corona
Kulimina Corona
OtohimeTholus
Table 2
Characteristics of the linear graben-fissure systems in the study area.
System
Longitude
(°E)
Latitude
(°S)
Length × width
(km)
Number of
mapped
lineaments
Centre
elevation
(km)
Elevation
above MPR
(km)
Centre
within
corona?
L01
L02
L03
L04
L05
L06
L07
L08
L09
L10
L11
L12
266.00
264.50
263.00
273.75
274.00
260.25
275.50
262.25
266.25
264.25
266.25
271.25
26.50
29.00
29.75
27.75
31.50
25.25
30.50
27.00
30.50
26.75
30.75
31.00
393 × 148
343 × 134
341 × 104
195 × 43
187 × 73
164 × 56
152 × 54
150 × 54
143 × 58
108 × 54
92 × 40
88 × 107
248
87
133
79
122
119
194
84
236
82
49
157
6052.7
6052.4
6052.5
6052.3
6052.0
6052.9
6052.2
6052.6
6051.6
6051.8
6051.7
6052.5
1.7
1.4
1.5
1.3
1.0
1.9
1.2
1.6
0.6
0.8
0.7
1.5
N
N
N
N
Y
N
Y
Y
N
N
N
N
Associated
structure
Obiemi Corona
Gertjon Corona
Kulimina Corona
Table 3
Characteristics of the circumferential graben-fissure systems in the study area.
System
Longitude
(°E)
Latitude
(°S)
Max
radius
(km)
Arc (°)
Number of
mapped
lineaments
Centre
elevation
(km)
Elevation
above MPR
(km)
Centre
within
corona?
C01
C02
C03
C04
C05
C06
C07
269.00
262.25
265.75
275.75
273.00
269.50
269.75
25.25
27.50
24.50
31.75
27.50
25.25
28.00
138
121
75
74
70
52
39
360
130/90
320
280
300
330
340
273
89
119
45
30
97
34
6052.1
6052.6
6051.7
6052.6
6053.3
6051.3
6052.9
1.1
1.6
0.7
1.6
2.3
0.3
1.9
Y
Y
Y
Y
N
Y
Y
Associated
structure
Hervor Corona
Kulimina Corona
Chuku Corona
Obiemi Corona
Ts’an Nu Mons
Hervor Corona
Xmukane Corona
J.R. Graff et al. / Icarus 306 (2018) 122–138
127
Fig. 3. Distribution of radiating (R#), linear (L#), and circumferential (C#) graben-fissure systems within the study area. Blue and yellow stars denote centres of radiating and
circumferential systems, respectively; purple hexagons indicate central positions of linear systems. Number coding corresponds to the mapped systems that are catalogued
in Tables 1–3. The location of topographic troughs, coinciding with Parga Chasma, is indicated in grey. The study area is indicated by the black rectangle.
7 (54%) exhibit a combination of younger and synchronous relationships, while the remaining 6 (46%) exhibit a combination of
older and synchronous relationships.
The results from this relative chronology and the detailed
linework mapping have been superimposed onto a SAR image of
the study area (Fig. 7). Graben-fissure systems of all sizes are
evenly distributed throughout the study area, but the largest ones
are found in association with coronae (R01–R03, R05) or large volcanoes (R04). There are also some locations, such as within the
areal extent of Kulimina Corona (e.g. systems R05 and R06) and
in the vicinity of Cryptic Centre 1, that contains dense clusters of
mostly smaller systems. These locations also host the majority of
young systems interpreted to postdate regional rifting. Many of the
largest systems are also among the youngest systems (with R03 as
a notable exception).
Importantly, all local magmatic centres that are interpreted as
the focal points for local triple-junction rifting contain graben-
fissure systems that are observed to cross-cut regional rift faults.
These age relationships provide evidence in support of multiple
stages of Parga Chasma rifting – beginning from regional NE–SW
extension between Atla and Themis Regiones and followed by local rifting events extending from individual magmatic centres.
6. Local triple-junction rifting
Throughout the study area prominent extension has occurred,
interpreted to be associated with both regional and local rifting
of the Parga Chasma rift system. Regional rifting is interpreted to
having resulted from large-scale NE–SW extension and observed
as a pattern of NW–SE oriented rift faults extending across the
study area (Fig. 8). Distinct from the regional pattern, local rifting
is observed as individual segments (also marked by topographic
troughs) extending from individual magmatic centres (Figs. 9–14,
Table 4).
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J.R. Graff et al. / Icarus 306 (2018) 122–138
Fig. 4. Distribution of rift faults within the study area. Topographic troughs are indicated in grey.
Fig. 5. Locations of figures found in Supplementary File 1.
J.R. Graff et al. / Icarus 306 (2018) 122–138
129
Fig. 6. Timeline of the tectono-magmatic events in the study area. The regional rifting of Parga Chasma is taken as the baseline (grey rectangle). Systems are numbered from
top to bottom with horizontal lines representing their interpreted age ranges relative to each other and to the regional rifting. Older systems are placed towards the left
side; younger systems towards the right. Systems interpreted to be synchronous with regional rifting intersect the baseline. Local rift fault segments are listed in parentheses
next to the system(s) to which they are genetically linked. Numbering is the same as in Tables 1–4 and Figs. 3, 4, 7, 9–13.
Within the study area, all local rift zones can be linked to
individual magmatic centres acting as the focal points of triplejunction rifting. Some of these centres are coronae, while the rest
are large volcanoes or cryptic centres, the latter only recognized as
the loci of radiating graben-fissure systems. In cases where there is
no central volcano-tectonic edifice or caldera above a centre, then
we label this as a ‘cryptic centre’. Similar cryptic centres have been
noted in Ernst et al. (2003) and Studd et al. (2011). Each of the
magmatic centres (whether cryptic or not) are hypothesized to be
formed from a mantle upwelling (Ernst and Buchan, 1997; Her-
rick, 1999; Ernst et al., 2001).These upwellings may be linked to
rising mantle plumes or originate from lithospheric delamination
(e.g. Şengör, 2001; Şengör and Natal’in, 2001; Ernst, 2014). Mantle plumes are likely candidates based on plume-induced triplejunction rifting having been extensively observed and described in
terrestrial settings (cf. Burke and Dewey, 1973; Şengör and Natal’in,
2001).
Ts’an Nu Mons (Fig. 10) is interpreted to be the magmatic
source of two separate rift zones, extending to the west (RF02) and
to the southeast (RF03) of the volcano. Xmukane Corona (Fig. 11)
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J.R. Graff et al. / Icarus 306 (2018) 122–138
Fig. 7. Magellan SAR image of the study area (50% transparency), superimposed with detailed linework of all radiating and linear graben-fissure systems, which are colourcoded as in Fig. 3. System centres are identified by circles which are sized and coloured according to maximum system radius/length and relative age, respectively.
Table 4
Local rift zones catalogued in the study area.
Rift zone
Number of rift faults
Associated magmatic centre
Trend (with respect to centre)
RF02
RF03
RF04
RF05
RF06
RF07
RF08
RF09
RF10
RF11
RF12
52
64
202
23
75
136
67
51
174
43
129
Ts’an Nu Mons
Ts’an Nu Mons
Xmukane Corona
Xmukane Corona
Xmukane Corona
Kulimina Corona
Kulimina Corona
Kulimina Corona
Cryptic Centre 2
Cryptic Centres 1 & 2
Cryptic Centre 1
West
Southeast
Northwest
Northeast
South
Northwest
East
East-southeast
Northwest
Southeast/northwest
Southeast
is the focus of three separate rift zones, extending to the northeast (RF04), the northwest (RF05), and the south (RF06). Kulimina Corona (Fig. 12) is at the centre of three rift zones, extending
to the northwest (RF07), the east (RF08), and the east-southeast
(RF09).Cryptic Centre 2 (Fig. 13) is centred on a northwest trending
rift zone (RF10), in addition to a segment trending to the southeast (RF11)—this latter segment also connects with Cryptic Centre
1. Cryptic Centre 1 (Fig. 13) is also the centre of a rift zone extending to the southeast (RF12). Combining these observations at
a local scale yields a summary map of the study area that displays
the five major magmatic centres interpreted to be the foci for associated local triple-junction rifting (Fig. 14).
The detailed mapping and analysis of the local rift fault pattern
throughout the study area has revealed numerous local rift trends
and provided the necessary information to group these rift faults
into local rift zones. In turn, grouping these local rift zones allowed
them to be linked to specific magmatic centres from which they
extend. The magmatic centres are typically marked by coronae,
large volcanoes, or radiating and/or circumferential graben-fissure
systems. Note that there are two radiating systems not associated
with any observed centrally located volcano-tectonic structure and
J.R. Graff et al. / Icarus 306 (2018) 122–138
131
Fig. 8. Magellan SAR image of the study area superimposed with linework corresponding to the regional rift fault pattern (light blue). The arrows denote the regional NE-SW
extension of Parga Chasma.
Fig. 9. Magellan SAR image of the study area superimposed with linework corresponding to the local rift faults which are further grouped into separate rift zones based on
lineament orientation. Local rift zones are labelled according to the data catalogued in Table 4.
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J.R. Graff et al. / Icarus 306 (2018) 122–138
Fig. 10. Local rifting associated with Ts’an Nu Mons. (a) Magellan SAR image. (b) Image overlain with mapping of local rift faults and segment lines (RF02, RF03) extending
from Ts’an Nu Mons (dark blue). Arrows denote direction of opening. See Fig. 9 for image location. (For interpretation of the references to colour in this figure legend, the
reader is referred to the web version of this article.)
Fig. 11. Local rifting associated with Xmukane Corona. (a) Magellan SAR image. (b) Image overlain with mapping of local rift faults and segment lines extending from
Xmukane Corona (turquoise). Arrows denote direction of opening. See Fig. 9 for image location. (For interpretation of the references to colour in this figure legend, the
reader is referred to the web version of this article.)
Fig. 12. Local rifting associated with Kulimina Corona. (a) Magellan SAR image. (b) Image overlain with mapping of local rift faults and segment lines extending from
Kulimina Corona (green). Arrows denote direction of extension. See Fig. 9 for image location. (For interpretation of the references to colour in this figure legend, the reader
is referred to the web version of this article.)
we have referred to these as “cryptic” (per the criteria mentioned
above). When several mantle upwellings occur in a zone of regional extension and crustal thinning, these magmatic centres can
collectively produce the morphology of a large, but often discontinuous rift system.
6.1. BAT region rift systems as collections of local rifting events
In the previous section it was postulated that a major section of
Parga Chasma can be interpreted as a collection of separate local
rift zones, formed via triple-junction rifting from individual magmatic centres. This section explores the possibility that insights
from our detailed mapping can be applied throughout the BAT
region. Specifically, we consider the model that individual mag-
matic centres can act as similar loci of triple-junction rifting along
other parts of Parga Chasma as well as throughout other major rift
systems of the BAT region. This hypothesis is formulated to explain the observed discontinuities in the morphologies of rift zones
throughout Hecate and Parga Chasmata. Such discontinuities are
apparent in the map presented in Graff et al. (2015) which was derived using tools in ArcMap to combine attributes from topography
and slope data (zones of relatively steeper slopes and topographic
lows) to automatically generate a rift map of the BAT region (Fig.
15). By contrast, the morphology of Devana Chasma can simply
be explained as the result of triple-junction rifting extending from
only the two major volcanic rises of Beta and Phoebe Regiones
at the ends of this single rift system (cf. Kiefer and Swafford,
2006).
J.R. Graff et al. / Icarus 306 (2018) 122–138
133
Fig. 13. Local rifting associated with the two cryptic magmatic centres. (a) Magellan SAR image. (b) Image overlain with mapping of local rift faults and segment lines
extending from Cryptic Centre 1 (orange) and Cryptic Centre 2 (magenta). Rift zone RF11 connects the two centres and is coloured in both orange and magenta. Arrows
denote direction of extension. See Fig. 9 for image location. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of
this article.)
Fig. 14. Magellan SAR image of the study area superimposed by a summary of all magmatic centres interpreted to be the foci of individual triple-junction rifting; rift zones
and centres are coloured-coded based on this interpreted association. Arrows denote direction of local extension.
The procedure for identifying individual large-scale rift segments across the entirety of Hecate and Parga Chasmata is that of
Graff et al. (2015) which is described in Section 3.3 of this paper.
Augmented by the data obtained from the automatically generated
‘rift candidacy map’ (Fig. 15), the preliminary identification of rift
zones comes primarily by locating the large zones of topographic
lows (indicating valleys) and relatively steeper slopes (marking the
walls of rift bounding faults). Cross-examining these locations with
the more detailed SAR images further allow us to locate rift zones
by looking for the presence of radar-bright lineaments indicative
of rift faults. With these locations identified they were then traced
out to capture the overall trend of the individual segments.
After each segment was identified, each end or junction point
along its length was carefully examined for the presence of a volcanic or magmatic structure in the form of either a volcano or
corona. The identification of these structures was also further confirmed by using a catalogue of geological features published by
the USGS (http://astrogeology.usgs.gov/). In the rare instance that
a junction point lacked a volcano or corona structure, close examination of the radar-bright lineaments revealed the presence of at
least one radiating or circumferential graben-fissure system, indicating a magmatic source in the nearby vicinity.
Applying the methodology from the detailed mapping in the
study area along Parga Chasma, we similarly interpret that Hecate
Chasma is composed of 13 local rift zones (Fig. 16, Table 5), in-
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J.R. Graff et al. / Icarus 306 (2018) 122–138
Fig. 15. Distribution of rifts in the BAT region of Venus (modified after Graff et al., 2015). Areas in red show the locations of major rift systems as automatically calculated
by the ArcMap geographical information system, using the approach discussed in Graff et al. (2015), superimposed on a topography map at 50% transparency (source: USGS
http://astrogeology.usgs.gov/). The black rectangle indicates the area of Parga Chasma mapped in detail in this study. Using tools available in ArcMap’s ArcToolbox function
(such as ‘hillshade relief’, ‘raster reclassify’, and ‘weighted sum’ [ESRI ArcGIS Resources (2014) http://resources.arcgis.com/en/home/]), we were able to combine attributes
from topography and slope data to delineate zones of topographic lows and relatively steeper slopes to automatically generate a map highlighting all candidate areas for rift
system locations.
Table 5
Rift zone groups along Hecate Chasma.
Rift zone group
Number of local segments
Number of associated magmatic centres
Type(s) of centre(s)
RZG01(Atla Regio)
RZG02(Beta Regio)
RZG03
RZG04
RZG05
RZG06
RZG07
2
1
2
2
1
3
2
1
1
1
1
1
2
2
Volcanic rise
Volcanic rise
Graben-fissure system
Corona
Corona
Corona and graben-fissure system
Corona
cluding those extending directly from the main plumes and associated triple-junction rifting of Atla and Beta Regiones at the ends
of the overall rift system. We propose that Parga Chasma contains
as many as 45 local rift zones throughout its full length (Fig. 17,
Table 6). Most of these local rift zones are linked to a corona or
large volcano, but some segments are observed to be isolated from
any corona or volcano. However, in such cases, graben-fissure systems mark cryptic magmatic centres from which separate local rift
zones extend.
6.2. Terrestrial analogue to Hecate and Parga Chasmata
The discontinuous morphology of rift systems, coupled with the
interpretation of regional formation via local rifting from multiple
magmatic centres, may not be confined only to Venus. On Earth,
the pre-spreading configuration of the Atlantic Rift System exhibits
local centres of rifting along its full extent that are similar to those
observed along both Hecate and Parga Chasmata (Fig. 17). In addition, the rifting and subsequent opening of the Atlantic Ocean is
linked to the arrival of at least three large mantle plumes, each
of which resulted in the formation of a large igneous province
(Ernst, 2014). Thus, there are many similarities between the terrestrial rifting (prior to ocean opening) of the Atlantic Rift System
and the Venusian rifting of Hecate and Parga Chasmata can be observed. It is clear from comparing Fig. 18b and c and Fig. 17a that
local rift centres are characteristic of both the BAT region and Atlantic Rift System, but the discontinuous aspect of rifting between
the local centres in the Venusian rifts is not apparent for the Atlantic Rift System (Fig. 18c, modified from the schematic diagram
of Sengor (1995)). However, such discontinuities in the Atlantic Rift
System are implied by the existence of local centres (from which
rifting should nucleate outward). This is well established for the
J.R. Graff et al. / Icarus 306 (2018) 122–138
135
Fig. 16. Magellan SAR images of Hecate Chasma (centred at 240°E, 16°N). (a) Image overlain by ungrouped local rift zones (purple lines) and corona locations (red stars). (b)
Local rift zones and magmatic centres organized into rift zone groups (RZG) and colour-coded to represent genetic association. Stars represent coronae, while circles denote
radiating and/or circumferential graben-fissure systems. Rift zone groups are catalogued in Table 5. (For interpretation of the references to colour in this figure legend, the
reader is referred to the web version of this article.)
Table 6
Rift zone groups along Parga Chasma.
Rift zone group
Number of local segments
Number of associated magmatic centres
Type(s) of centre(s)
RZG01
RZG02
RZG03 (Atla Regio)
RZG04
RZG05
RZG06
RZG07
RZG08
RZG09 (Kulimina)
RZG10
RZG11
RZG12 (Cryptic Centres 1 and 2)
RZG13
RZG14 (Xmukane)
RZG15 (Ts’an Nu Mons)
RZG16
RZG17
RZG18
RZG19
RZG20
RZG21
RZG22
2
2
4
3
1
3
3
3
3
2
2
3
1
3
2
2
1
1
1
1
1
1
1
1
3
2
1
1
1
1
1
1
2
2
1
1
1
2
1
1
1
1
1
2
Corona
Corona
Corona and volcanic rise
Corona
Corona
Corona
Corona
Graben-fissure system
Corona
Graben-fissure system
Corona
Graben-fissure system
Corona
Corona
Volcano
Corona
Corona
Corona
Corona
Corona
Corona
Corona
rift systems of the northern, central and southern Atlantic given
the distinct differences in timing of rifting in these regions, c. 55,
190 and 120 Ma, respectively. Some rift discontinuities do seem
to be present in the more detailed rift maps of Sengor and Natalin (2001), but a more comprehensive study of the entire Atlantic
Rift System would be required to fully characterize the pattern of
discontinuities along its length. To summarize, each rift system:
(1) exhibits similar discontinuous morphology; (2) contains major
plume-related magmatic centres, likely acting as a primary cause
of rifting; and (3) contain smaller centres that display local triplejunction rifting. A difference between the Atlantic Rift System and
the situation on Venus is that on Earth the various rift segments
succeeded in opening the Central, Southern, and Northern Atlantic
Oceans (at times, ∼190, ∼120, and ∼55 Ma), while the Venusian
examples failed to progress to an ocean opening stage.
Drawing further comparisons between terrestrial and Venusian
rifting involves the age relationships between the rifting events
and their interpreted magmatic centres. In the case of the Atlantic
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J.R. Graff et al. / Icarus 306 (2018) 122–138
Fig. 17. Magellan SAR images of Parga Chasma (centred at 245°E, 20°S). (a) Image overlain by ungrouped local rift zones (purple lines) and corona locations (red stars). (b)
Local rift zones and magmatic centres organized into rift zone groups (RZG) and colour-coded to represent genetic association. Stars represent coronae, while circles denote
radiating and/or circumferential graben-fissure systems. Rift zone groups are catalogued in Table 6. (For interpretation of the references to colour in this figure legend, the
reader is referred to the web version of this article.)
Rift System each of the main plume centres were emplaced at different times over a range of ∼140 million years (200, 135, and
62 Ma, with ocean opening starting approximately 10 Ma later in
each case; see Fig. 11.2 and text in Ernst (2014) for details). The
separate triple-junctions focussed on each main plume centre are
also interpreted to have formed synchronously (±∼10–20 Ma) with
their associated plume centre (Ernst, 2014). With respect to Venusian rifting, the relative chronology of magmatic events within the
study area leads a comparable result. Notably, the magmatic centres (and associated graben-fissure systems) linked to local rift
zones in the study area(Ts’an Nu Mons (R04); Xmukane Corona
(R01); Kulimina Corona (R05); Cryptic Centre 1 (R07); and Cryptic Centre 2 (R16)) have all been dated via cross-cutting relationships as younger than the regional rifting of Parga Chasma and
synchronous with formation with their associated triple-junction
rift zones.
7. Conclusions
While previous extensional lineament studies primarily focussed on graben-fissure systems (e.g. Grosfils and Head, 1994a,b;
Ernst et al., 2003; Studd et al., 2011), this study included the identification of rift zones and detailed mapping of the associated rift
faults along a 1500 km segment of Parga Chasma. Clusters of rift
faults and graben-fissures were grouped into 11 local rift zones and
47 graben-fissure systems, respectively. Regional rifting of Parga
Chasma exhibits an overall NW-SE extension pattern that is interpreted to have preceded local rifting events extending from individual magmatic centres located along the rift system. Each such
magmatic centre was interpreted as the locus for the coeval development of a radiating graben-fissure system and associated local
triple-junction rifting. A similar model of overall regional extension
and subsequent localization into local triple-junction rift zones is
also applied to the rest of Parga Chasma and the entirety of Hecate
Chasma.
Comparable rift morphology is also observed in examples from
Earth, notably along the ∼15,0 0 0 km Atlantic Rift System. The prespreading morphology of this giant terrestrial rift system exhibits
similar discontinuities in the rift pattern to those observed along
Hecate and Parga Chasmata. The rifting of the Atlantic Rift System
(prior to ocean opening in each segment) has also formed from
the arrival of at least three separate mantle plumes and several
smaller local events, each causing local triple-junction rifting that
collectively developed into the complex morphology of a complete
rift system. This observation further supports our local rift model
hypothesis, implying that major Venusian and terrestrial rift sys-
J.R. Graff et al. / Icarus 306 (2018) 122–138
137
Fig. 18. Comparison between the Atlantic Rift System with the schematic morphology of Hecate and Parga Chasmata. Atlantic Rift System diagram modified from Fig. 11.2
in Ernst (2014) which was modified after Fig. 2.7B in Şengör (1995). The St. Helena plume centre is proposed after Hollanda et al. (2016). All three diagrams are at the same
scale. The Hecate and Parga Chasmata maps are extracted from Figs. 16 and 17.
tems can be identified as a collection of local triple-junction rifting events focussed on individual magmatic centres along a larger
regional rift system.
Acknowledgements
This research was supported by a NSERC Discovery Grant
awarded to Richard Ernst. In addition, Richard Ernst has been partially supported by Russian Government grant no. 14.Y26.31.0012.
Two anonymous reviewers and journal editor Professor Oded
Aharonson are thanked for their thoughtful suggestions.
Supplementary materials
Supplementary material associated with this article can be
found, in the online version, at doi:10.1016/j.icarus.2018.02.010.
References
Airey, M.W., Mather, T.A., Pyle, D.M., Ghail, R.C., 2017. The distribution of volcanism
in the Beta-Atla-Themis region for Venus: its relationship to rifting and implications for global tectonic regimes. J. Geophys. Res.: Planets 122, 1626–1649.
Brakenridge, G.R., Anderson, E.K., Finnegan, D.C., 20 0 0. Geological mapping of V26
Atla Regio Quadrangle, Venus: evidence for an extinct plate boundary. Lunar
Planet. Sci. XXXI Abstract 1914.
Burke, K., Dewey, J., 1973. Plume-generated triple junctions: key indicators in applying plate tectonics to old rocks. J. Geol. 81, 406–433.
Chaisson, E., McMillan, S., 2010. Astronomy today. In: The Solar System, 1. seventh
ed. Addison-Wesley Publishing, San Francisco, CA, pp. 211–229. Chapter 9.
Crumpler, L.S., Aubele, J.C., 20 0 0. Volcanism on Venus. In: Encyclopedia of Volcanoes. Academic, San Diego, California, pp. 727–770.
Davies, M.E., Colvin, T.R., Rogers, P.G., Chodas, P.W., Sjogren, W.L., Akim, E.L., Stepanyantz, V.A., Vlasova, Z.P., Zakharov, A.I., 1992. The rotation period, direction
of the north pole, and geodetic control network of Venus. J. Geophys. Res. 97,
13141–13151.
Donahue, T.M., Russell, C.T., 1997. The Venus atmosphere and ionosphere and their
interaction with the solar wind: an overview. In: Bougher, S.W., Hunten, D.M.,
Phillips, R.J. (Eds.), Venus II: Geology, Geophysics, Atmosphere, and Solar Wind
Environment. University of Arizona Press, Tucson, AZ, pp. 3–31.
Ernst, R.E., 2014. Large Igneous Provinces. Cambridge University Press 653 p.
Ernst, R.E., Buchan, K.L., 1997. Giant radiating dyke swarms: their use in identifying
pre-Mesozoic large igneous provinces and mantle plumes. In: AGU Geophysical
Monograph, 100, pp. 297–333.
Ernst, R.E., Buchan, K.L., 2001. The use of mafic dyke swarms in identifying and
locating mantle plumes. In: Ernst, R.E., Buchan, K.L. (Eds.), Mantle Plumes: Their
Identification Through Time. Geological Society of America, Boulder, CO, Special
Paper 352, pp. 483–575.
Ernst, R.E., Desnoyers, D.W., 2004. Lessons from Venus for understanding mantle
plumes on Earth. Phys. Earth Planet. Interiors 146, 195–229.
Ernst, R.E., Desnoyers, D.W., Head, J.W., Grosfils, E.B., 2003. Graben-fissure systems
in Guinevere Planitia and Beta Regio (264°-312°E, 24°-60°N), Venus, and implications for regional stratigraphy and mantle plumes. Icarus 164, 282–316.
Ernst, R.E., Grosfils, E.B., Head, J.W., Samson, C., Ivanov, M.A., Studd, D., Harris, B.A.,
2009. Towards a dyke swarm map of Venus. Eos Trans. AGU 90 (22) (Jt. Assem.
Suppl.), GA13A-06.
Ernst, R.E., Grosfils, E.B., Mege, D., 2001. Giant dyke swarms: Earth, Venus, Mars.
Annu. Rev. Earth Planet. Sci. 29, 489–534.
Graff, J.R., 2016. A History of Tectono-Magmatism along the Parga Chasma Rift System on Venus. Department of Earth Sciences, Carleton University M.Sc. thesis.
Graff, J.R., Ernst, R.E., Samson, C., 2015. Delineating rift faults on radar images in
Hecate Chasma, Venus. Lunar Planet. Sci. XXXXVI Abstract 2217.
Grosfils, E.B., Head, J.W., 1994a. The global distribution of giant radiating dike
swarms on Venus: implications for the global stress state. Geophys. Res. Lett.
21, 701–704.
Grosfils, E.B., Head, J.W., 1994b. Emplacement of a radiating dike swarm in western
Vinmara Planitia, Venus: implication of the regional stress field orientation and
subsurface magmatic configuration. Earth, Moon Planets 66, 153–171.
Hamilton, V.E., Stofan, E.R., 1996. The geomorphology and evolution of Hecate
Chasma, Venus. Icarus 121, 171–194.
Hansen, V.L., DeShon, H.R., 2003. Geologic Map of the Diana Chasma Quadrangle (V37), Venus. U.S. Geological Survey Geologic Investigations Series I-2752 https:
//pubs.usgs.gov/imap/i2752/.
Hansen, V.L., Young, D.A., 2007. Venus’ evolution: a synthesis. In: Cloos, M., Carlson, W.D., Gilbert, M.C., Liou, J.G., Sorensen, S.S. (Eds.), Convergent Margin Terranes and Associated regions: a Tribute to W.G. Ernst, Geological Society of
America Special Paper 419, pp. 255–273.
Hazlett, R.W., Hyndman, D.W., 1996. Roadside Geology of Hawaii. Mountain Press,
Missoula, MT 307 p.
Head, J.W., 2014. The geologic evolution of Venus: insights into Earth history. Geology 42, 95–96.
Head, J.W., Crumpler, L.S., Aubele, J.C., Guest, J.E., Saunders, R.S., 1992. Venus volcanism: classification of volcanic features and structures, associations, and global
distribution from Magellan data. J. Geophys. Res. 97, 13153–13197.
Herrick, R.R., 1999. Small mantle upwellings are pervasive on Venus and Earth. Geophys. Res. Lett. 26, 803–806.
Hollanda, M.H.B.M., Archanjo, C.J., Renne, P.R., Ngonge, D.E., Castro, D.L.,
Oliveira, D.C., Macêdo Filho, A.A., 2016. Evidence of an early cretaceous giant
138
J.R. Graff et al. / Icarus 306 (2018) 122–138
dyke swarm in northeast Brazil (South America): a geodynamic overview. Acta
Geol. Sin. (English Edition) 90 (Supp. 1) Abstract of the Seventh International
Dyke Conference, “Dyke Swarms: Keys to Paleogeographic Reconstruction” August 18-20, 2016.
Ivanov, M.A., Head, J.W., 2011. Global geological map of Venus. Planet. Space Sci. 59,
1559–1600.
Ivanov, M.A., Head, J.W., 2013. A history of volcanism on Venus. Planet. Space Sci.
84, 66–92.
Kiefer, W.S., Swafford, L.C., 2006. Topographic analysis of Devana Chasma, Venus:
implications for rift system segmentation and propagation. J. Struct. Geol. 28,
2144–2155.
López, I., Hansen, V.L., 2008. Geologic map of the Helen Planitia Quadrangle (V-52),
Venus. U.S. Geological Survey Scientific Investigations Map 3026. http://pubs.
usgs.gov/sim/3026/.
Mark, C., Gupta, S., Carter, A., Mark, D.F., Gautheron, C., Martin, A., 2014. Rift flank
uplift at the Gulf of California: no requirement for asthenospheric upwelling.
Geology 42, 259–262.
Martin, P., Stofan, E.R., 2004. Coronae of Parga Chasma, Venus. Lunar Planet. Sci.
XXXV Abstract 1576.
Martin, P., Stofan, E.R., Glaze, L.S., Smrekar, S., 2007. Coronae of Parga Chasma,
Venus. J. Geophys. Res. 112, E04S03.
Nimmo, F., McKenzie, D., 1998. Volcanism and tectonics on Venus. Annu. Rev. Earth
Planet. Sci. 26, 23–51.
Phillips, R.J., Hansen, V.L., 1994. Tectonic and magmatic evolution of Venus. Annu.
Rev. Earth Planet. Sci. 22, 597–654.
Saunders, R.S., Pettengill, G.H., Arvidson, R.E., Sjogren, W.L., Johnson, W.T.K.,
Pieri, L., 1990. The Magellan Venus radar mapping mission. J. Geophys. Res. 95,
8339–8355.
Saunders, R.S., Pettengill, G.H., 1991. Magellan mission summary. Science 252,
247–249.
Saunders, R.S., Spear, A.J., Allin, P.C., Austin, R.S., Berman, A.L., Chandlee, R.C.,
Clark, J., DeCharron, A.V., De Jong, E.M., Griffifith, D.G., Gunn, J.M., Hensley, S.,
Johnson, W.T.K., Kirby, C.E., Leung, K.S., Lyons, D.T., Michaels, G.A., Miller, J., Morris, R.B., Piereson, R.G., Scott, J.F., Shaffer, S.J., Slonski, J.P., Stofan, E.R., Thompson, T.W., Wall, S.D., 1992. Magellan mission summary. J. Geophys. Res. 97,
13067–13090.
Şengör, A.M.C., 1995. Sedimentation and tectonics of fossil rifts. In: Busby, C.J., Ingersoll, R.-V. (Eds.), Tectonics of Sedimentary Basins. Blackwell, Oxford, pp. 53–117.
Şengör, A.M.C., 2001. Elevation as indicator of mantle-plume activity. In: Ernst, R.E.,
Buchan, K.L. (Eds.), Mantle Plumes: Their Identification Through Time, Geological Society of America Special Paper 352, pp. 183–225.
Şengör, A.M.C., Natal’in, B.A., 2001. Rifts of the world. In: Ernst, R.E., Buchan, K.L.
(Eds.), Mantle Plumes: Their Identification Through Time, Geological Society of
America Special Paper 352, pp. 389–482.
Senske, D.A., Schaber, G.G., Stofan, E.R., 1992. Regional topographic rises on Venus:
geology of western Eistla Regio and comparison to Beta Regio and Atla Regio. J.
Geophys. Res. 97, 13395–13420.
Smrekar, S.E., Kiefer, W.S., Stofan, E.R. 1997. Large volcanic rises on Venus. Lunar and
Planetary Exploration Technical Report, NASA/CR-97-205865; NAS 1.26:205865.
Solomatov, V.S., Moresi, L.N., 1996. Stagnant lid convection on Venus. J. Geophys.
Res. 101, 4737–4753.
Stofan, E.R., Smrekar, S.E., Bindschadler, D.L., Senske, D.A., 1995. Large topographic
rises on Venus: implications for mantle upwelling. J. Geophys. Res. 100,
23317–23327.
Stofan, E.R., Smrekar, S.E., Martin, P., 20 0 0. Coronae of Parga Chasma, Venus: implications for Chasma and corona evolution. Lunar Planet. Sci. XXXI Abstract 1578.
Studd, D., Ernst, R.E., Samson, C., 2011. Radiating graben-fissure systems in the Ulfrun Regio Area, Venus. Icarus 215, 279–291.
Studd, D., Ernst, R.E., Samson, C., Grosfils, E.B., Head, J.W., Ivanov, M.A., 2010a. Radiating graben-fissure systems in Ulfrun Regio: a contribution to the Venus global
dyke swarm map project. Lunar Planet. Sci. XXXXI Abstract 1950.
Studd, D., Ernst, R.E., Samson, C., Grosfils, E.B., Head, J.W., Ivanov, M.A., 2010b. Mapping in the Ulfrun Regio area: a contribution towards a global Venus dyke
swarm map. CASI ASTRO Con. 15, #03.
Studd, D., Ernst, R.E., Samson, C., Grosfils, E.B., Head, J.W., Ivanov, M.A., 2010c. Interaction between radiating graben-fissure systems and local geology, Ulfrun Regio,
Venus: a contribution to the Venus global dyke swarm map project. COSPAR Sci.
Ass. 38 B-10-0 0 0 0-10.
Taylor, F.W., 2014. The Scientific Exploration of Venus. Cambridge University Press
295 p.
Torske, T., 1975. Possible Mesozoic mantle plume activity beneath the continental
margin of Norway. Norges Geol. Unders. 322, 73–90.
Turcotte, D.L., 1995. How does Venus lose heat? J. Geophys. Res. 100, 16931–16940.
Young, C., 1990. The Magellan Venus Explorer’s Guide. NASA-JPL, Pasadena, CA Publication 90-24.
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