Mosasaur taphonomy in Pierre Shale Formation, South Dakota + large igneous provinces in Triassic and Guadalupian (Middle Permian) extinctions
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Ben Creisler
Jan 27, 2026, 5:16:07 PM (6 days ago) Jan 27
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Ben Creisler
The trigger for frequent extinctions during the Phanerozoic remains a persistent and unresolved frontier issue in Earth sciences. We present a detailed analysis of oceanic island, seamount, and plateau remnants in the Tibetan Plateau that trace the evolution of the Meso- and Neo-Tethys oceans, incorporating new and published data. During the Triassic, three major episodes of marine large igneous provinces (LIPs) formed at 250−248 Ma, 233−231 Ma, and 210−208 Ma. By integrating geological records of these LIP episodes with Triassic geological data sets, we demonstrate a correlation between marine LIPs and at least four extinctions in marine biota, driven by the resultant anoxic-euxinic events. Consequently, marine LIPs emerge as a primary driver of recurrent mass extinctions. Numerous previously unexplained extinctions throughout Earth’s history may potentially result from currently unidentified components of marine LIPs occurring as fragments within orogenic belts.
***
News:
Marine volcanic plateaus tied to at least 4 Triassic extinction events
https://phys.org/news/2026-01-marine-volcanic-plateaus-triassic-extinction.html
Recent papers:
Andrew Rich & Sarah W. Keenan (2026)
Mosasaur taphonomy from the Sharon Springs member of the Pierre Shale Formation, South Dakota
PALAIOS 41(1): 24–35.
DOI: https://doi.org/10.2110/palo.2024.002
https://pubs.geoscienceworld.org/sepm/palaios/article-abstract/41/1/24/725272/MOSASAUR-TAPHONOMY-FROM-THE-SHARON-SPRINGS-MEMBER
The Pierre Shale Formation is a well-studied fossiliferous marine shale unit that spans a large portion of western North America. In South Dakota, the Pierre Shale Formation is divided by the Missouri River into two geographic regions: the Black Hills Region to the west and the Central/Eastern Region to the east. Both regions have extensive outcrops, including exposures of the Sharon Springs Member. The Sharon Springs Member preserves an abundance of invertebrate and vertebrate fossils, including mosasaurs. Given that fossil-rich outcrops of the Sharon Springs occur in both geographic regions, this study aimed to analyze trends in preservation of mosasaur fossils to determine if there are significant differences in the degree of weathering and geochemistry of fossils. The degree of subaerial and submarine weathering, as indicated by gypsum encrustation and abrasion, was characterized based on physical evidence of alteration. X-ray fluorescence was used to determine the geochemical composition of fossil specimens, including phosphorus (P), sulfur (S), strontium (Sr), and iron (Fe). The mosasaur fossils displayed statistically significant differences in the degrees of weathering across the two regions (p = 0.005) and fossils recovered from the Black Hills Region were more highly weathered. Fossils examined from the Central/Eastern region contained significantly higher Fe concentrations (mean: 62578 ppm) compared to the Black Hills Region (mean: 26438 ppm). The average P, S, and Sr content of fossils preserved in the two regions were not significantly different. Fossils from both regions display high variability in chemical composition, likely reflecting the dynamic nature of early diagenesis and taphonomy. These results suggest that Fe in vertebrate fossils may be a useful indicator of diagenetic conditions in the Western Interior Seaway.
Mosasaur taphonomy from the Sharon Springs member of the Pierre Shale Formation, South Dakota
PALAIOS 41(1): 24–35.
DOI: https://doi.org/10.2110/palo.2024.002
https://pubs.geoscienceworld.org/sepm/palaios/article-abstract/41/1/24/725272/MOSASAUR-TAPHONOMY-FROM-THE-SHARON-SPRINGS-MEMBER
The Pierre Shale Formation is a well-studied fossiliferous marine shale unit that spans a large portion of western North America. In South Dakota, the Pierre Shale Formation is divided by the Missouri River into two geographic regions: the Black Hills Region to the west and the Central/Eastern Region to the east. Both regions have extensive outcrops, including exposures of the Sharon Springs Member. The Sharon Springs Member preserves an abundance of invertebrate and vertebrate fossils, including mosasaurs. Given that fossil-rich outcrops of the Sharon Springs occur in both geographic regions, this study aimed to analyze trends in preservation of mosasaur fossils to determine if there are significant differences in the degree of weathering and geochemistry of fossils. The degree of subaerial and submarine weathering, as indicated by gypsum encrustation and abrasion, was characterized based on physical evidence of alteration. X-ray fluorescence was used to determine the geochemical composition of fossil specimens, including phosphorus (P), sulfur (S), strontium (Sr), and iron (Fe). The mosasaur fossils displayed statistically significant differences in the degrees of weathering across the two regions (p = 0.005) and fossils recovered from the Black Hills Region were more highly weathered. Fossils examined from the Central/Eastern region contained significantly higher Fe concentrations (mean: 62578 ppm) compared to the Black Hills Region (mean: 26438 ppm). The average P, S, and Sr content of fossils preserved in the two regions were not significantly different. Fossils from both regions display high variability in chemical composition, likely reflecting the dynamic nature of early diagenesis and taphonomy. These results suggest that Fe in vertebrate fossils may be a useful indicator of diagenetic conditions in the Western Interior Seaway.
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Jian-Jun Fan, Si-Lin Sun, Jian-Bo Zhou, Simon A. Wilde, Yang Wang & Jun-Pu Lv (2026)
Marine large igneous provinces: Key drivers of Triassic recurrent extinction
Geology (advance online publication)
DOI: https://doi.org/10.1130/G53406.1
https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G53406.1/724643/Marine-large-igneous-provinces-Key-drivers-of
Geology (advance online publication)
DOI: https://doi.org/10.1130/G53406.1
https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G53406.1/724643/Marine-large-igneous-provinces-Key-drivers-of
The trigger for frequent extinctions during the Phanerozoic remains a persistent and unresolved frontier issue in Earth sciences. We present a detailed analysis of oceanic island, seamount, and plateau remnants in the Tibetan Plateau that trace the evolution of the Meso- and Neo-Tethys oceans, incorporating new and published data. During the Triassic, three major episodes of marine large igneous provinces (LIPs) formed at 250−248 Ma, 233−231 Ma, and 210−208 Ma. By integrating geological records of these LIP episodes with Triassic geological data sets, we demonstrate a correlation between marine LIPs and at least four extinctions in marine biota, driven by the resultant anoxic-euxinic events. Consequently, marine LIPs emerge as a primary driver of recurrent mass extinctions. Numerous previously unexplained extinctions throughout Earth’s history may potentially result from currently unidentified components of marine LIPs occurring as fragments within orogenic belts.
***
News:
Marine volcanic plateaus tied to at least 4 Triassic extinction events
https://phys.org/news/2026-01-marine-volcanic-plateaus-triassic-extinction.html
====
Hengye Wei, Xuan Zhang & Zhen Qiu (2026)
Pulsed volcanism of the Emeishan large igneous province caused the Guadalupian (Middle Permian) mass extinction
GSA Bulletin (advance online publication
doi: https://doi.org/10.1130/B38771.1
https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B38771.1/724706/Pulsed-volcanism-of-the-Emeishan-large-igneous
Supervolcano eruptions have played a major role in the evolution of life and environments on Earth. The Emeishan large igneous province (LIP) eruptive activity had been suggested to be the cause of the Guadalupian (Middle Permian) mass extinction event and the transition from icehouse to greenhouse climate in the Permian. However, the causal mechanism of the Emeishan LIP’s impact on the environment and mass extinction is still unresolved. This study presents >300 foraminiferal species, mercury (Hg) and carbon isotopic compositions, zircon U-Pb ages, biomarkers, and elemental data across the Guadalupian-Lopingian (G-L; i.e., middle−upper Permian) boundary of South China to investigate mass extinction and the evolution of the Emeishan LIP. A precise chronological framework across the G-L boundary is reconstructed using five U-Pb age data integrated with carbon isotopic stratigraphic correlations. A U-Pb age of 260.58 ± 0.86 Ma determined using secondary ion mass spectrometry from a section of continuous deposition is suggested as a revised age for the G-L boundary. Organic carbon isotopic composition (δ13Corg) and Hg geochemistry data show three pulses of Emeishan LIP eruptive activity in the earliest Wordian, in the middle Capitanian, and at the G-L boundary, respectively. The second and third pulses of the Emeishan LIP eruptive activity in the middle Capitanian and at the G-L boundary, respectively, coincided with two stages of the Guadalupian mass extinction, demonstrating a causal link. The Emeishan LIP eruptive activity probably caused the Guadalupian mass extinction by triggering marine anoxia and global warming.
Pulsed volcanism of the Emeishan large igneous province caused the Guadalupian (Middle Permian) mass extinction
GSA Bulletin (advance online publication
doi: https://doi.org/10.1130/B38771.1
https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B38771.1/724706/Pulsed-volcanism-of-the-Emeishan-large-igneous
Supervolcano eruptions have played a major role in the evolution of life and environments on Earth. The Emeishan large igneous province (LIP) eruptive activity had been suggested to be the cause of the Guadalupian (Middle Permian) mass extinction event and the transition from icehouse to greenhouse climate in the Permian. However, the causal mechanism of the Emeishan LIP’s impact on the environment and mass extinction is still unresolved. This study presents >300 foraminiferal species, mercury (Hg) and carbon isotopic compositions, zircon U-Pb ages, biomarkers, and elemental data across the Guadalupian-Lopingian (G-L; i.e., middle−upper Permian) boundary of South China to investigate mass extinction and the evolution of the Emeishan LIP. A precise chronological framework across the G-L boundary is reconstructed using five U-Pb age data integrated with carbon isotopic stratigraphic correlations. A U-Pb age of 260.58 ± 0.86 Ma determined using secondary ion mass spectrometry from a section of continuous deposition is suggested as a revised age for the G-L boundary. Organic carbon isotopic composition (δ13Corg) and Hg geochemistry data show three pulses of Emeishan LIP eruptive activity in the earliest Wordian, in the middle Capitanian, and at the G-L boundary, respectively. The second and third pulses of the Emeishan LIP eruptive activity in the middle Capitanian and at the G-L boundary, respectively, coincided with two stages of the Guadalupian mass extinction, demonstrating a causal link. The Emeishan LIP eruptive activity probably caused the Guadalupian mass extinction by triggering marine anoxia and global warming.
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