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Climatic reversals related to the Central Atlantic magmatic province caused the end-Triassic biotic crisis; evidence from continental strata in Poland

Grzegorz Pienkowski, Grzegorz Niedzwiedzki and Pawel Branski
Climatic reversals related to the Central Atlantic magmatic province caused the end-Triassic biotic crisis; evidence from continental strata in Poland (in Volcanism, impacts, and mass extinctions; causes and effects, Gerta Keller (editor) and Andrew C. Kerr (editor))
Special Paper - Geological Society of America (September 2014) 505: 263-286

Abstract

Eight climatic events can be distinguished in the Triassic-Jurassic (ca. 201 Ma) continental strata of Poland. These events are distinguished by kaolinite/illite ratio, chemical index of alteration (CIA), color of sediments, and palynomorphs. The first transition to wetter climate, evidenced by a shift from smectite- to kaolinite-dominated mudrocks, coincides with the earlier ("precursor") Rhaetian negative delta (super 13) C (sub org) excursion, which means that the beginning of climate perturbations predates the oldest known Central Atlantic magmatic province flood basalts by some 100-200 k.y. The later global, late Rhaetian "initial" negative delta (super 13) C (sub org) excursion is divided into two subpeaks, each corresponding to hot and humid events, separated by a cooler and drier event. The upper subpeak is also associated with perturbation of the osmium isotope system (attributed to volcanic fallout), and darkened miospores, pointing to acid rains. Between the "initial" excursion and the Triassic-Jurassic boundary interval, five climatic fluctuations are inferred from the changing kaolinite/illite ratio, the last two of which are also associated with an Os isotope perturbation, polycyclic aromatic hydrocarbon (PAH) occurrences, a "spore peak," and darkened miospores. A series of periodic atmospheric loading events by CO (sub 2) , CH (sub 4) , or alternatively by SO (sub 2) , sulfate aerosols, and toxic compounds, is inferred to have caused this series of rapid climatic reversals and resulting extinction of many less-adapted forms. Just above the palynofloral extinction level, appearance of new forms commenced Jurassic palynofloral recovery. Tetrapod evolution events in the end-Triassic-earliest Jurassic were related to the extinction of the Pseudosuchia, Dicynodontia, Capitosauroidea, Plagiosaroidea, and Rhynchosauria, while appearance of highly diversified tetrapod ichnofauna in the earliest Jurassic strata indicates a rapid recovery and refill of ecological niches by dinosaurs.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 505
Title: Climatic reversals related to the Central Atlantic magmatic province caused the end-Triassic biotic crisis; evidence from continental strata in Poland
Title: Volcanism, impacts, and mass extinctions; causes and effects
Author(s): Pienkowski, GrzegorzNiedzwiedzki, GrzegorzBranski, Pawel
Author(s): Keller, Gertaeditor
Author(s): Kerr, Andrew C.editor
Affiliation: Polish Geological Institute, National Research Institute, Warsaw, Poland
Affiliation: Princeton University, Department of Geosciences, Princeton, NJ, United States
Pages: 263-286
Published: 201409
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 150
Accession Number: 2014-085282
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. cols., 1 table, sketch map
N49°00'00" - N54°45'00", E14°15'00" - E24°15'00"
Secondary Affiliation: Cardiff University, GBR, United KingdomUppsala University, SWE, Sweden
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201444
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