Infrazonal ammonite biostratigraphy of the Upper Kimmeridgian of Polish Lowland (preliminary results) and Late Kimmeridgian eventsкод для вставки
Infrazonal ammonite biostratigraphy of the Upper Kimmeridgian of Polish Lowland (preliminary results) and Late Kimmeridgian events Mikhail Rogov, Geological Institute of RAS, Moscow, Russia 1. Review of previous studies 1. Review of previous studies 1. Review of previous studies 1. Review of previous studies 1. Review of previous studies 2. Material Upper Kimmeridgian is mainly belonging to clayey Paluki Formation 2. Material Dr. Jan Kutek (1935-2013) in his room, Warsaw University (2006) 2. Material Excellent collection of cores is stored in the Polish Geological Institute, Warsaw (studied in the years 2008 and 2013) 3. Results Amoebites kapffi, Volga river Amoebites kapffi, Pasłęk IG 1, from Wierzbowski et al., 2015 Aulacostephanoides linealis, Kcynia I Amoebites kapffi, Kcynia I ?Zenostephanus sp., Kcynia I Amoebites salfeldi, N. Siberia Mutabilis Zone Amoebites salfeldi, Kcynia I Sarygulia cf. pischmae, Kcynia I 3. Results Aulacostephanus eudoxus, Kcynia I Orthaspidoceras cf. lallierianum, Kcynia IV Ochetoceras canaliferum, Kcynia I Sarygulia sp. juv., Kcynia I Glochiceras nimbatum, Kcynia I Aulacostephanus cf. yo, Kcynia IV Eudoxus Zone 3. Results Euprionoceras sokolovi, Borow K36 Aspidoceras cf. quercynum Gostynin IG 4 Aulacostephanus yo, Gostynin IG 4 Nannocardioceras ex gr. anglicum, Nidzica 1 Hoplocardioceras sp., Borow K36 Eudoxus Zone Nannocardioceras ex gr. anglicum, Gorodischi Nannocardioceras ex gr. anglicum, Kcynia I Nannocardioceras ex gr. anglicum, N. Siberia 3. Results Aspidoceras cf. catalaunicum, Kcynia I Schaireria sp., Nidzica 1 A. autissiodorensis, Gostynin IG 4 Sutneria sp. n. aff. rebholzi, Nidzica 1 A. autissiodorensis, Piotrkow Trybunalski Autissiodorensis Zone Nannocardioceras volgae, Nowostawy 3. Results Sarmatisphinctes zeissi, Borow K36 Sarmatisphinctes zeissi, Zosin 54-52 Tolvericeras cf. murogense, Gostynin IG 4 1591,8 Autissiodorensis Zone Sarmatisphinctes subborealis, Kcynia I Sarmatisphinctes zeissi, Aulacostephanus mammatus, Płońsk 8 3. Results Infrazonal subdivision of the Upper Kimmeridgian of Polish Lowland and its correlation with succession of the European part of Russia 3. Results Black shales Ammonite assemblages of the Upper Kimmeridgian of Poland 3. Results Decline of aulacostephanids at the end of the Kimmeridgian, Black Head section, Dorset Black shales are typical for anglicum horizon and its correlatives throughout the Subboreal areas Conclusions • Ammonite succession of the Upper Kimmeridgian of Polish Lowland is very close to those of the European part of Russia in the both taxonomic composition of ammonoid assemblages and change of dominant taxa through time • At least few remarkable events characterized by abrupt changes of Boreal to Submediterranean ammonite dominance are well-recognized throughout the Subboreal section. Such changes could be possible related to either climate oscillations or palaeoceanographic changes • Appearance of the last cardioceratid genus Nannocardioceras, characterized by dwarf size and mass occurrences in all Subboreal areas, is marked by presence of OM-enriched black shales. • Last cardioceratids (Nannocardioceras volgae) throughout the Subboreal areas occurred in very thin bands (some 10-20 cm in thickness), and duration of the volgae hemera (timeequivalent of the volgae biohorizon) could be as short as 10 000 - 20 000 years • Gradual disappearance of aulacostephanids during the Autissiodorensis Chron is traced in all Subboreal areas, and extinction of this family could be used as marker of the upper boundary of the KImmeridgian Stage Thanks for your attention!