End-Permian vertebrate-extinction model for Karoo Basin incorrect + Grippia bonebed taphonomy + Middle Triassic succession in Svalbard + more
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Ben Creisler
May 6, 2026, 6:15:58 PM (10 days ago) May 6
to DinosaurMa...@googlegroups.com
Ben Creisler
Recent papers:
Robert A. Gastaldo, Johann Neveling, Sandra L. Kamo, Solomon O. Akatakpo, John W. Geissman, Heriberto Rochín-Bañaga & Neil Tabor (2026)
Conundrums of Wapadsberg Pass and other locales in the Karoo Basin, South Africa: The death knell of the end-Permian vertebrate-extinction model
GSA Bulletin (advance online publication)
doi: https://doi.org/10.1130/B38563.1
https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B38563.1/730393/Conundrums-of-Wapadsberg-Pass-and-other-locales-in
Over the past 30 years, the vertebrate-fossil record of the Karoo Basin, South Africa, has served as a model for the coeval response of terrestrial ecosystems with the end-Permian marine extinction event. This model presumes a vertebrate-assemblage turnover involving the replacement of synapsids and other tetrapods with diagnostic taxa of the Lystrosaurus declivis Assemblage Zone in the Palingkloof Member, Balfour Formation, and is based on collections from a small number of Eastern Cape and southernmost Free State province localities. Although there are previous tests of the Karoo Basin extinction model at the classic Free State and Eastern Cape province localities, this contribution further tests the current vertebrate extinction model with a multidisciplinary dataset from the classic localities in and around Wapadsberg Pass in the Eastern Cape Province.
We present an expanded lithostratigraphic framework, encompassing ∼800 m of measured and correlated sections, extending over an ∼6 km distance northward from the New Wapadsberg Pass locality. To this we add U-Pb chemical abrasion−isotope dilution−thermal ionization mass spectrometry dates from three beds yielding detrital zircons; details on magnetic polarity stratigraphy information from 11 sites in sedimentary strata above an Early Jurassic Karoo sill and related rock magnetic data; and stable δ13C and δ18O data from calcite-cemented pedogenic nodules from paleosols, supplementing previously published data and augmenting prior interpretations.
We demonstrate that previously reported high-resolution biostratigraphic schemes are not stratigraphically constrained to the intervals to which they were assigned. These stratigraphic subunits cannot be correlated across the study area over a distance of <2 km. The stratigraphic frameworks established at both the Wapadsberg and the adjacent Lootsberg Pass localities reveal a complicated sedimentary montage in the stratigraphic record of the Balfour and Katberg formations, complicating high-resolution comparison. We conclude from our independent, and a posteriori, tests that the prevailing Karoo Basin vertebrate-extinction paradigm violates fundamental biostratigraphic principles and that the terrestrial end-Permian mass extinction model on which it is based should be abandoned in the Karoo Basin and globally.
Maciej Ruciński, Aubrey Roberts, Øyvind Hammer, Benjamin P. Kear & Jørn Hurum (2026)
Taphonomy of the Lower Triassic (Spathian) Grippia Bonebed from Central Spitsbergen (Svalbard): Biostratinomic, palaeoenvironmental and palaeoecological perspectives
Palaeogeography, Palaeoclimatology, Palaeoecology 113844
doi: https://doi.org/10.1016/j.palaeo.2026.113844
https://www.sciencedirect.com/science/article/pii/S003101822600307X
Highlights
First comprehensive taphonomic analysis of the Lower Triassic Grippia Bonebed.
Hydraulic concentration and condensation during transgression formed the deposit.
Early phosphatisation and low-oxygen bottom waters enhanced preservation.
Assemblage is nekton-dominated, pointing to potentially inhospitable bottom waters.
Preservation and sampling biases unevenly affect invertebrates and vertebrates.
Abstract
Lower Triassic deposits of the Vikinghøgda Formation on Spitsbergen yield diverse assemblages of chondrichthyans, actinopterygians, coelacanths, lungfish, temnospondyls, and marine reptiles. These fossils mainly occur in three stratigraphic levels spanning the middle Smithian to upper Spathian, documenting key stages of marine vertebrate recovery ~2-4 million years after the end-Permian mass extinction (EPME). In 2015–2016, ~36 m2 of the lower Spathian Grippia Bonebed was excavated, yielding thousands of isolated skeletal elements within a dense multi-taxic Konzentrat-Lagerstätte. Here, we present a taphonomic analysis of the Grippia Bonebed to reconstruct the processes of its formation and assess potential taphonomic biases. The deposit is a clast-supported conglomerate composed of bones and coprolites within silty shale facies representing a distal shelf palaeoenvironment. Skeletal elements show varying post-mortem transport alterations, with a low to moderate degree of abrasion. The assemblage formed via hydrodynamic concentration, possibly by storm-driven deposition. The high density of fossils and minimal sediment volume suggest condensation of the accumulated elements, while suboxic to anoxic conditions and phosphatisation enhanced preservation potential. Taphonomic and sampling biases impact taxonomic representation, particularly at lower trophic levels. These are manifested by dissolution of invertebrates and underrepresentation of some vertebrate groups, particularly actinopterygians, due to selective preservation of poorly diagnostic elements. Consequently, this study is the first documentation of a Lower Triassic marine bonebed formed in a distal shelf setting and one of the oldest phosphate clast accumulations following the EPME, offering new insights into early Mesozoic ecosystems and refining a framework for global comparisons of similar deposits.
Victoria S. Engelschiøn, Øyvind Hammer, Fredrik Wesenlund, Jørn H. Hurum & Atle Mørk (2025)
Palaeoenvironment and new chemostratigraphic markers for the Middle Triassic succession in Svalbard
Norwegian Journal of Geology 105(3): 1-45
https://dx.doi.org/10.17850/njg105-3-2
https://njg.geologi.no/publications/palaeoenvironment-and-new-chemostratigraphic-markers-for-the-middle-triassic-succession-in-svalbard/
This study presents a detailed analysis of the Middle Triassic Botneheia Formation in Svalbard, integrating sedimentology, geochemistry and palaeontology to understand the depositional environment. Fieldwork was conducted at five localities in central Spitsbergen and Edgeøya, with two additional localities in western Spitsbergen and Bjørnøya for comparison. Three carbon-isotope excursions are identified for the first time in the Botneheia Formation in central Spitsbergen and on Edgeøya—the positive Olenekian–Anisian Carbon Isotope Excursion (OACIE), negative Anisian–Ladinian Isotopic Carbon Excursion (ALICE), and positive Ladinian–Carnian Carbon Isotope Excursion (LICE). It is possible that OACIE is also present in western Spitsbergen and Bjørnøya and that LICE extends to Bjørnøya. We discuss their potential use as regional chronostratigraphic markers, drawing global comparisons. Systematic documentation of body and trace fossils from bulk sediment samples reveals benthic fossils in 153 out of 339 samples, and a higher diversity especially of bivalves than previously assumed for the Botneheia Formation. There are notable differences in benthic diversity and oxygenation between central Spitsbergen and Edgeøya, with lower diversities in the east, associated with more dysoxic conditions. These differences may be linked to the Ural Delta approaching from the east causing algal blooms and haloclines already in the Middle Triassic. The combination of geochemical proxies with fossil assemblages provides a detailed reconstruction of a Boreal Sea seabed during the Middle Triassic and highlights the influence of fluctuating oxygen levels in shaping benthic ecosystems and depositional environments.
Douwe J. J. van Hinsbergen, Bram Vaes, Lydian M. Boschman, Nalan Lom, Suzanna H. A. van de Lagemaat, Eldert L. Advokaat, Sanne de Baar, Menno R. T. Fraters, Joren Paridaens & Emilia B. Jarochowska (2026)
Paleolatitude.org 3.0: A calculator for paleoclimate and paleobiology studies based on a new global paleogeography model
PLoS One 21(4): e0346817.
doi: https://doi.org/10.1371/journal.pone.0346817
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0346817
Paleogeography, and particularly the paleolatitude, provides key context in the interpretation of paleoclimatic and paleobiological data but these fields are typically studied by scientists in different disciplines. To facilitate communication between these disciplines, a decade ago the online Paleolatitude.org calculator was developed. This provided for any coordinate on stable tectonic plates a paleolatitude estimate for any chosen Phanerozoic time interval, including an uncertainty that includes paleogeographic uncertainty and age uncertainty of a sample/fossil. Here, we provide a major update to this tool. First, we include in the calculator the first global paleogeographic model, including GPlates reconstruction files, back to 320 Ma that also restores paleogeographic units that are now thrusted over each other in orogenic (mountain) belts. Second, we include a recent, more precise paleomagnetic reference frame with updated statistical procedures, and provide the first update of its underlying database. Third, we introduce a new online interface with an easy-to-use tool with a batch option, and data and graph export functions. Finally, we illustrate differences with previous reconstructions and show an application by calculating a paleolatitudinal biodiversity gradient for the late Jurassic in which we use a bootstrap approach to propagate paleolatitude and age uncertainty into the result.
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Robert A. Gastaldo, Johann Neveling, Sandra L. Kamo, Solomon O. Akatakpo, John W. Geissman, Heriberto Rochín-Bañaga & Neil Tabor (2026)
Conundrums of Wapadsberg Pass and other locales in the Karoo Basin, South Africa: The death knell of the end-Permian vertebrate-extinction model
GSA Bulletin (advance online publication)
doi: https://doi.org/10.1130/B38563.1
https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B38563.1/730393/Conundrums-of-Wapadsberg-Pass-and-other-locales-in
Over the past 30 years, the vertebrate-fossil record of the Karoo Basin, South Africa, has served as a model for the coeval response of terrestrial ecosystems with the end-Permian marine extinction event. This model presumes a vertebrate-assemblage turnover involving the replacement of synapsids and other tetrapods with diagnostic taxa of the Lystrosaurus declivis Assemblage Zone in the Palingkloof Member, Balfour Formation, and is based on collections from a small number of Eastern Cape and southernmost Free State province localities. Although there are previous tests of the Karoo Basin extinction model at the classic Free State and Eastern Cape province localities, this contribution further tests the current vertebrate extinction model with a multidisciplinary dataset from the classic localities in and around Wapadsberg Pass in the Eastern Cape Province.
We present an expanded lithostratigraphic framework, encompassing ∼800 m of measured and correlated sections, extending over an ∼6 km distance northward from the New Wapadsberg Pass locality. To this we add U-Pb chemical abrasion−isotope dilution−thermal ionization mass spectrometry dates from three beds yielding detrital zircons; details on magnetic polarity stratigraphy information from 11 sites in sedimentary strata above an Early Jurassic Karoo sill and related rock magnetic data; and stable δ13C and δ18O data from calcite-cemented pedogenic nodules from paleosols, supplementing previously published data and augmenting prior interpretations.
We demonstrate that previously reported high-resolution biostratigraphic schemes are not stratigraphically constrained to the intervals to which they were assigned. These stratigraphic subunits cannot be correlated across the study area over a distance of <2 km. The stratigraphic frameworks established at both the Wapadsberg and the adjacent Lootsberg Pass localities reveal a complicated sedimentary montage in the stratigraphic record of the Balfour and Katberg formations, complicating high-resolution comparison. We conclude from our independent, and a posteriori, tests that the prevailing Karoo Basin vertebrate-extinction paradigm violates fundamental biostratigraphic principles and that the terrestrial end-Permian mass extinction model on which it is based should be abandoned in the Karoo Basin and globally.
====
Free pdf:
Maciej Ruciński, Aubrey Roberts, Øyvind Hammer, Benjamin P. Kear & Jørn Hurum (2026)
Taphonomy of the Lower Triassic (Spathian) Grippia Bonebed from Central Spitsbergen (Svalbard): Biostratinomic, palaeoenvironmental and palaeoecological perspectives
Palaeogeography, Palaeoclimatology, Palaeoecology 113844
doi: https://doi.org/10.1016/j.palaeo.2026.113844
https://www.sciencedirect.com/science/article/pii/S003101822600307X
Highlights
First comprehensive taphonomic analysis of the Lower Triassic Grippia Bonebed.
Hydraulic concentration and condensation during transgression formed the deposit.
Early phosphatisation and low-oxygen bottom waters enhanced preservation.
Assemblage is nekton-dominated, pointing to potentially inhospitable bottom waters.
Preservation and sampling biases unevenly affect invertebrates and vertebrates.
Abstract
Lower Triassic deposits of the Vikinghøgda Formation on Spitsbergen yield diverse assemblages of chondrichthyans, actinopterygians, coelacanths, lungfish, temnospondyls, and marine reptiles. These fossils mainly occur in three stratigraphic levels spanning the middle Smithian to upper Spathian, documenting key stages of marine vertebrate recovery ~2-4 million years after the end-Permian mass extinction (EPME). In 2015–2016, ~36 m2 of the lower Spathian Grippia Bonebed was excavated, yielding thousands of isolated skeletal elements within a dense multi-taxic Konzentrat-Lagerstätte. Here, we present a taphonomic analysis of the Grippia Bonebed to reconstruct the processes of its formation and assess potential taphonomic biases. The deposit is a clast-supported conglomerate composed of bones and coprolites within silty shale facies representing a distal shelf palaeoenvironment. Skeletal elements show varying post-mortem transport alterations, with a low to moderate degree of abrasion. The assemblage formed via hydrodynamic concentration, possibly by storm-driven deposition. The high density of fossils and minimal sediment volume suggest condensation of the accumulated elements, while suboxic to anoxic conditions and phosphatisation enhanced preservation potential. Taphonomic and sampling biases impact taxonomic representation, particularly at lower trophic levels. These are manifested by dissolution of invertebrates and underrepresentation of some vertebrate groups, particularly actinopterygians, due to selective preservation of poorly diagnostic elements. Consequently, this study is the first documentation of a Lower Triassic marine bonebed formed in a distal shelf setting and one of the oldest phosphate clast accumulations following the EPME, offering new insights into early Mesozoic ecosystems and refining a framework for global comparisons of similar deposits.
====
Free pdf:
Victoria S. Engelschiøn, Øyvind Hammer, Fredrik Wesenlund, Jørn H. Hurum & Atle Mørk (2025)
Palaeoenvironment and new chemostratigraphic markers for the Middle Triassic succession in Svalbard
Norwegian Journal of Geology 105(3): 1-45
https://dx.doi.org/10.17850/njg105-3-2
https://njg.geologi.no/publications/palaeoenvironment-and-new-chemostratigraphic-markers-for-the-middle-triassic-succession-in-svalbard/
This study presents a detailed analysis of the Middle Triassic Botneheia Formation in Svalbard, integrating sedimentology, geochemistry and palaeontology to understand the depositional environment. Fieldwork was conducted at five localities in central Spitsbergen and Edgeøya, with two additional localities in western Spitsbergen and Bjørnøya for comparison. Three carbon-isotope excursions are identified for the first time in the Botneheia Formation in central Spitsbergen and on Edgeøya—the positive Olenekian–Anisian Carbon Isotope Excursion (OACIE), negative Anisian–Ladinian Isotopic Carbon Excursion (ALICE), and positive Ladinian–Carnian Carbon Isotope Excursion (LICE). It is possible that OACIE is also present in western Spitsbergen and Bjørnøya and that LICE extends to Bjørnøya. We discuss their potential use as regional chronostratigraphic markers, drawing global comparisons. Systematic documentation of body and trace fossils from bulk sediment samples reveals benthic fossils in 153 out of 339 samples, and a higher diversity especially of bivalves than previously assumed for the Botneheia Formation. There are notable differences in benthic diversity and oxygenation between central Spitsbergen and Edgeøya, with lower diversities in the east, associated with more dysoxic conditions. These differences may be linked to the Ural Delta approaching from the east causing algal blooms and haloclines already in the Middle Triassic. The combination of geochemical proxies with fossil assemblages provides a detailed reconstruction of a Boreal Sea seabed during the Middle Triassic and highlights the influence of fluctuating oxygen levels in shaping benthic ecosystems and depositional environments.
====
Free pdf:
Douwe J. J. van Hinsbergen, Bram Vaes, Lydian M. Boschman, Nalan Lom, Suzanna H. A. van de Lagemaat, Eldert L. Advokaat, Sanne de Baar, Menno R. T. Fraters, Joren Paridaens & Emilia B. Jarochowska (2026)
Paleolatitude.org 3.0: A calculator for paleoclimate and paleobiology studies based on a new global paleogeography model
PLoS One 21(4): e0346817.
doi: https://doi.org/10.1371/journal.pone.0346817
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0346817
Paleogeography, and particularly the paleolatitude, provides key context in the interpretation of paleoclimatic and paleobiological data but these fields are typically studied by scientists in different disciplines. To facilitate communication between these disciplines, a decade ago the online Paleolatitude.org calculator was developed. This provided for any coordinate on stable tectonic plates a paleolatitude estimate for any chosen Phanerozoic time interval, including an uncertainty that includes paleogeographic uncertainty and age uncertainty of a sample/fossil. Here, we provide a major update to this tool. First, we include in the calculator the first global paleogeographic model, including GPlates reconstruction files, back to 320 Ma that also restores paleogeographic units that are now thrusted over each other in orogenic (mountain) belts. Second, we include a recent, more precise paleomagnetic reference frame with updated statistical procedures, and provide the first update of its underlying database. Third, we introduce a new online interface with an easy-to-use tool with a batch option, and data and graph export functions. Finally, we illustrate differences with previous reconstructions and show an application by calculating a paleolatitudinal biodiversity gradient for the late Jurassic in which we use a bootstrap approach to propagate paleolatitude and age uncertainty into the result.
===
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