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Frank Scholze - One of the best experts on this subject based on the ideXlab platform.
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late paleozoic early mesozoic continental biostratigraphy links to the standard global chronostratigraphic scale
Palaeoworld, 2020Co-Authors: Frank Scholze, Spencer G. Lucas, Hendrik Klein, Joerg W Schneider, Sebastian Voigt, Lorenzo Marchetti, Stanislav Oplustil, Ralf Werneburg, V. K. GolubevAbstract:Abstract Nonmarine biostratigraphic/biochronologic schemes have been created for all or parts of the late Carboniferous–Middle Triassic using palynomorphs, megafossil plants, conchostracans, blattoid insects, tetrapod footprints and tetrapod body fossils, and these provide varied temporal resolution. Cross correlation of the nonmarine biochronologies to the Standard Global Chronostratigraphic Scale has been achieved in some parts of the late Carboniferous–Middle Triassic in locations where nonmarine and marine strata are intercalated, the nonmarine strata produce biochronologically significant fossils and the marine strata yield fusulinids, conodonts and/or ammonoids. Other cross correlations have been aided by magnetostratigraphy, chemostratigraphy and a growing database of radioisotopic ages. A synthetic nonmarine biochronology for the late Carboniferous–Middle Triassic based on all available nonmarine index fossils, integrated with the Standard Global Chronostratigraphic Scale, is presented here. The focus is on the nonmarine biostratigraphy/biochronology of blattoid insects, conchostracans, branchiosaurid amphibians, tetrapod footprints and tetrapod body fossils within the biochronological framework of land-vertebrate faunachrons. Correlation to the Standard Global Chronostratigraphic Scale presented here is divided into seven time intervals: Pennsylvanian, Carboniferous–Permian boundary, Cisuralian, Guadalupian, Lopingian, Permian–Triassic boundary and Early to Middle Triassic. The insects, conchostracans and branchiosaurs provide robust nonmarine correlations in the Pennsylvanian–Cisuralian, and the footprints and tetrapod body fossils provide robust correlations of varied precision within the entire Pennsylvanian–Middle Triassic. Radioisotopic ages are currently the strongest basis for cross correlation of the nonmarine biostratigraphy/biochronology to the Standard Global Chronostratigraphic Scale, particularly for the Pennsylvanian–Cisuralian. Chemostratigraphy and magnetostratigraphy thus far provide only limited links of nomarine and marine chronologies. Improvements in the nonmarine-marine correlations of late Paleozoic–Triassic Pangea require better alpha taxonomy and stratigraphic precision for the nonmarine fossil record integrated with more reliable radioisotopic ages and more extensive chemostratigraphic and magnetostratigraphic datasets.
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early Triassic conchostracans crustacea branchiopoda from the terrestrial permian Triassic boundary sections in the moscow syncline
Palaeogeography Palaeoclimatology Palaeoecology, 2015Co-Authors: Grzegorz Niedźwiedzki, Frank Scholze, V. K. Golubev, A. G. Sennikov, Jörg W. Schneider, Vladimir V. SilantievAbstract:Abstract The Permian–Triassic boundary marks the greatest mass extinction in Earth's history. In order to understand the real causes of this severe extinction event, multidisciplinary investigations around the globe are required. Here, the terrestrial Permian–Triassic boundary sections in the Vladimir region, Central Russia, were sampled bed-by-bed for conchostracan study. In the Early Triassic intervals the following taxa were recognized for the first time: Cornia germari (Beyrich, 1857), Euestheria gutta (Lutkevitch, 1937), Magniestheria mangaliensis (Jones, 1862), Palaeolimnadiopsis vilujensis Varentsov, 1955, and Rossolimnadiopsis Novozhilov, 1958. The wide distribution of C. germari demonstrates their high value for biostratigraphy, since this species was also reported from the Lower Buntsandstein Subgroup in the Germanic Basin as well as from Early Triassic deposits in Hungary, Greenland and Siberia. The assumption of an Early Triassic age of the studied sections is also supported by associated Tupilakosaurus bone fragments, which point to the Tupilakosaurus wetlugensis Zone in the earliest Triassic.
Michael J. Benton - One of the best experts on this subject based on the ideXlab platform.
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The origin of endothermy in synapsids and archosaurs and arms races in the Triassic
Gondwana Research, 2020Co-Authors: Michael J. BentonAbstract:Abstract Birds and mammals are key elements of modern ecosystems, and many biologists explain their great success by their endothermy, or warm-bloodedness. New palaeontological discoveries point to the origins of endothermy in the Triassic, and that birds (archosaurs) and mammals (synapsids) likely acquired endothermy in parallel. Here, a further case is made, that the emergence of endothermy in a stepwise manner began in the Late Permian but accelerated in the Early Triassic. The trigger was the profound destruction wrought by the Permian-Triassic mass extinction (PTME). In the oceans, this was the beginning of the Mesozoic Marine Revolution (MMR), and a similar revolution occurred on land, termed here the Triassic Terrestrial Revolution (TTR). Among tetrapods, both synapsids and archosaurs survived into the Triassic, but numbers were heavily depleted. However, the survivors were marked by the acquisition of endothermy, as shown by bone histology, isotopic analyses, and the acquisition of insulating pelage. Both groups before the PTME had been sprawlers; after the event they adopted parasagittal (erect) gait. The new posture and the new physiology enabled both groups to compete in their ecosystems at a faster rate than before the PTME. The new world of the Triassic was characterised by a fast-paced arms race between synapsids and archosauromorphs in which the latter, as both dinosaurs and pterosaurs, initially prevailed.
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a gigantic nothosaur reptilia sauropterygia from the middle Triassic of sw china and its implication for the Triassic biotic recovery
Scientific Reports, 2015Co-Authors: Jun Liu, Michael J. Benton, Olivier Rieppel, Dayong Jiang, Neil P Kelley, Jonathan C Aitchison, Changyong Zhou, Wen Wen, Jinyuan Huang, Tao XieAbstract:The presence of gigantic apex predators in the eastern Panthalassic and western Tethyan oceans suggests that complex ecosystems in the sea had become re-established in these regions at least by the early Middle Triassic, after the Permian-Triassic mass extinction (PTME). However, it is not clear whether oceanic ecosystem recovery from the PTME was globally synchronous because of the apparent lack of such predators in the eastern Tethyan/western Panthalassic region prior to the Late Triassic. Here we report a gigantic nothosaur from the lower Middle Triassic of Luoping in southwest China (eastern Tethyan ocean), which possesses the largest known lower jaw among Triassic sauropterygians. Phylogenetic analysis suggests parallel evolution of gigantism in Triassic sauropterygians. Discovery of this gigantic apex predator, together with associated diverse marine reptiles and the complex food web, indicates global recovery of shallow marine ecosystems from PTME by the early Middle Triassic.
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resetting the evolution of marine reptiles at the Triassic jurassic boundary
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Philippa M Thorne, Marcello Ruta, Michael J. BentonAbstract:Ichthyosaurs were important marine predators in the Early Jurassic, and an abundant and diverse component of Mesozoic marine ecosystems. Despite their ecological importance, however, the Early Jurassic species represent a reduced remnant of their former significance in the Triassic. Ichthyosaurs passed through an evolutionary bottleneck at, or close to, the Triassic-Jurassic boundary, which reduced their diversity to as few as three or four lineages. Diversity bounced back to some extent in the aftermath of the end-Triassic mass extinction, but disparity remained at less than one-tenth of pre-extinction levels, and never recovered. The group remained at low diversity and disparity for its final 100 Myr. The end-Triassic mass extinction had a previously unsuspected profound effect in resetting the evolution of apex marine predators of the Mesozoic.
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Macroevolutionary patterns in the evolutionary radiation of archosaurs (Tetrapoda: Diapsida)
Earth and Environmental Science Transactions of The Royal Society of Edinburgh, 2010Co-Authors: Stephen L. Brusatte, Michael J. Benton, Marcello Ruta, Graeme T. Lloyd, Steve C. WangAbstract:The rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morpho- logical disparity, rates of morphological character change, and faunal abundance during the Triassic-Early Jurassic. The fundamental archosaur lineages originated early in the Triassic, in concert with the highest rates of character change. Disparity and diversity peaked later, during the Norian, but the most significant increase in disparity occurred before maximum diversity. Archo- saurs were rare components of Early-Middle Triassic faunas, but were more abundant in the Late Triassic and pre-eminent globally by the Early Jurassic. The archosaur radiation was a drawn-out event and major components such as diversity and abundance were discordant from each other. Crurotarsans (crocodile-line archosaurs) were more disparate, diverse, and abundant than avemeta- tarsalians (bird-line archosaurs, including dinosaurs) during the Late Triassic, but these roles were reversed in the Early Jurassic. There is no strong evidence that dinosaurs outcompeted or gradually eclipsed crurotarsans during the Late Triassic. Instead, crurotarsan diversity decreased precipitously by the end-Triassic extinction, which helped usher in the age of dinosaurian dominance.
V. K. Golubev - One of the best experts on this subject based on the ideXlab platform.
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late paleozoic early mesozoic continental biostratigraphy links to the standard global chronostratigraphic scale
Palaeoworld, 2020Co-Authors: Frank Scholze, Spencer G. Lucas, Hendrik Klein, Joerg W Schneider, Sebastian Voigt, Lorenzo Marchetti, Stanislav Oplustil, Ralf Werneburg, V. K. GolubevAbstract:Abstract Nonmarine biostratigraphic/biochronologic schemes have been created for all or parts of the late Carboniferous–Middle Triassic using palynomorphs, megafossil plants, conchostracans, blattoid insects, tetrapod footprints and tetrapod body fossils, and these provide varied temporal resolution. Cross correlation of the nonmarine biochronologies to the Standard Global Chronostratigraphic Scale has been achieved in some parts of the late Carboniferous–Middle Triassic in locations where nonmarine and marine strata are intercalated, the nonmarine strata produce biochronologically significant fossils and the marine strata yield fusulinids, conodonts and/or ammonoids. Other cross correlations have been aided by magnetostratigraphy, chemostratigraphy and a growing database of radioisotopic ages. A synthetic nonmarine biochronology for the late Carboniferous–Middle Triassic based on all available nonmarine index fossils, integrated with the Standard Global Chronostratigraphic Scale, is presented here. The focus is on the nonmarine biostratigraphy/biochronology of blattoid insects, conchostracans, branchiosaurid amphibians, tetrapod footprints and tetrapod body fossils within the biochronological framework of land-vertebrate faunachrons. Correlation to the Standard Global Chronostratigraphic Scale presented here is divided into seven time intervals: Pennsylvanian, Carboniferous–Permian boundary, Cisuralian, Guadalupian, Lopingian, Permian–Triassic boundary and Early to Middle Triassic. The insects, conchostracans and branchiosaurs provide robust nonmarine correlations in the Pennsylvanian–Cisuralian, and the footprints and tetrapod body fossils provide robust correlations of varied precision within the entire Pennsylvanian–Middle Triassic. Radioisotopic ages are currently the strongest basis for cross correlation of the nonmarine biostratigraphy/biochronology to the Standard Global Chronostratigraphic Scale, particularly for the Pennsylvanian–Cisuralian. Chemostratigraphy and magnetostratigraphy thus far provide only limited links of nomarine and marine chronologies. Improvements in the nonmarine-marine correlations of late Paleozoic–Triassic Pangea require better alpha taxonomy and stratigraphic precision for the nonmarine fossil record integrated with more reliable radioisotopic ages and more extensive chemostratigraphic and magnetostratigraphic datasets.
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early Triassic conchostracans crustacea branchiopoda from the terrestrial permian Triassic boundary sections in the moscow syncline
Palaeogeography Palaeoclimatology Palaeoecology, 2015Co-Authors: Grzegorz Niedźwiedzki, Frank Scholze, V. K. Golubev, A. G. Sennikov, Jörg W. Schneider, Vladimir V. SilantievAbstract:Abstract The Permian–Triassic boundary marks the greatest mass extinction in Earth's history. In order to understand the real causes of this severe extinction event, multidisciplinary investigations around the globe are required. Here, the terrestrial Permian–Triassic boundary sections in the Vladimir region, Central Russia, were sampled bed-by-bed for conchostracan study. In the Early Triassic intervals the following taxa were recognized for the first time: Cornia germari (Beyrich, 1857), Euestheria gutta (Lutkevitch, 1937), Magniestheria mangaliensis (Jones, 1862), Palaeolimnadiopsis vilujensis Varentsov, 1955, and Rossolimnadiopsis Novozhilov, 1958. The wide distribution of C. germari demonstrates their high value for biostratigraphy, since this species was also reported from the Lower Buntsandstein Subgroup in the Germanic Basin as well as from Early Triassic deposits in Hungary, Greenland and Siberia. The assumption of an Early Triassic age of the studied sections is also supported by associated Tupilakosaurus bone fragments, which point to the Tupilakosaurus wetlugensis Zone in the earliest Triassic.
Spencer G. Lucas - One of the best experts on this subject based on the ideXlab platform.
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late paleozoic early mesozoic continental biostratigraphy links to the standard global chronostratigraphic scale
Palaeoworld, 2020Co-Authors: Frank Scholze, Spencer G. Lucas, Hendrik Klein, Joerg W Schneider, Sebastian Voigt, Lorenzo Marchetti, Stanislav Oplustil, Ralf Werneburg, V. K. GolubevAbstract:Abstract Nonmarine biostratigraphic/biochronologic schemes have been created for all or parts of the late Carboniferous–Middle Triassic using palynomorphs, megafossil plants, conchostracans, blattoid insects, tetrapod footprints and tetrapod body fossils, and these provide varied temporal resolution. Cross correlation of the nonmarine biochronologies to the Standard Global Chronostratigraphic Scale has been achieved in some parts of the late Carboniferous–Middle Triassic in locations where nonmarine and marine strata are intercalated, the nonmarine strata produce biochronologically significant fossils and the marine strata yield fusulinids, conodonts and/or ammonoids. Other cross correlations have been aided by magnetostratigraphy, chemostratigraphy and a growing database of radioisotopic ages. A synthetic nonmarine biochronology for the late Carboniferous–Middle Triassic based on all available nonmarine index fossils, integrated with the Standard Global Chronostratigraphic Scale, is presented here. The focus is on the nonmarine biostratigraphy/biochronology of blattoid insects, conchostracans, branchiosaurid amphibians, tetrapod footprints and tetrapod body fossils within the biochronological framework of land-vertebrate faunachrons. Correlation to the Standard Global Chronostratigraphic Scale presented here is divided into seven time intervals: Pennsylvanian, Carboniferous–Permian boundary, Cisuralian, Guadalupian, Lopingian, Permian–Triassic boundary and Early to Middle Triassic. The insects, conchostracans and branchiosaurs provide robust nonmarine correlations in the Pennsylvanian–Cisuralian, and the footprints and tetrapod body fossils provide robust correlations of varied precision within the entire Pennsylvanian–Middle Triassic. Radioisotopic ages are currently the strongest basis for cross correlation of the nonmarine biostratigraphy/biochronology to the Standard Global Chronostratigraphic Scale, particularly for the Pennsylvanian–Cisuralian. Chemostratigraphy and magnetostratigraphy thus far provide only limited links of nomarine and marine chronologies. Improvements in the nonmarine-marine correlations of late Paleozoic–Triassic Pangea require better alpha taxonomy and stratigraphic precision for the nonmarine fossil record integrated with more reliable radioisotopic ages and more extensive chemostratigraphic and magnetostratigraphic datasets.
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the late Triassic extinction at the norian rhaetian boundary biotic evidence and geochemical signature
Earth-Science Reviews, 2020Co-Authors: Manuel Rigo, Spencer G. Lucas, Mariachiara Zaffani, Kliti Grice, Tetsuji Onoue, Lawrence H Tanner, Linda Godfrey, Miriam E Katz, Jaime Cesar, Daisuke YamashitaAbstract:Abstract The latest Triassic was an interval of prolonged biotic extinction culminating in the end-Triassic Extinction (ETE). The ETE is now associated with a perturbation of the global carbon cycle just before the end of the Triassic that has been attributed to the extensive volcanism of the Circum-Atlantic Magmatic Province (CAMP). However, we attribute the onset of declining latest Triassic diversity to an older perturbation of the carbon cycle (δ13Corg) of global extent at or very close to the Norian/Rhaetian boundary (NRB). The NRB appears to be the culmination of stepwise biotic turnovers that characterize the latest Triassic and includes global extinctions of significant marine and terrestrial fossil groups. These biotic events across the NRB have been largely under-appreciated, yet together with a coeval disturbance of the carbon cycle were pivotal in the history of the Late Triassic. Here, we present new and published δ13Corg data from widespread sections (Italy, Greece, ODP, Australia, New Zealand, USA, Canada). These sections document a previously unknown perturbation in the carbon cycle of global extent that spanned the NRB. The disturbance extended across the Panthalassa Ocean to both sides of the Pangaean supercontinent and is recorded in both the Northern and Southern Hemispheres. The onset of stepwise Late Triassic extinctions coincides with carbon perturbation (δ13Corg) at the NRB, indicating that a combination of climatic and environmental changes impacted the biota at a global scale. The NRB event may have been triggered either by gas emissions from the eruption of a large igneous province pre-dating the NRB, by a bolide impact of significant size or by some alternative source of greenhouse gas emissions. As yet, it has not been possible to clearly determine which of these trigger scenarios was responsible; the evidence is insufficient to decisively identify the causal mechanism and merits further study.
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late Triassic terrestrial tetrapods biostratigraphy biochronology and biotic events
2018Co-Authors: Spencer G. LucasAbstract:The fossil record of Late Triassic tetrapods can be organized biostratigraphically and biochronologically into five, temporally successive land-vertebrate faunachrons (LVFs) that encompass Late Triassic time (in ascending order): Berdyankian, Otischalkian, Adamanian, Revueltian and Apachean. An up-to-date review of the age constraints on Late Triassic tetrapod fossil assemblages and correlation within the framework of the LVFs is presented. This makes possible a much more accurate evaluation of the timing of biotic events of Late Triassic tetrapod evolution, including: (1) Otischalkian, HO (highest occurrence) of almasaurids and chroniosuchians?, LOs (lowest occurrences) of crocodylomorphs and dinosaurs; (2) Adamanian, HO of mastodonsaurids and trematosaurids, LO of mammals; (3) Revueltian, HOs of capitosaurids, rhynchosaurs and dicynodonts; and (4) Apachean, HOs of metoposaurids, plagiosaurids and aetosaurs. The LO of turtles is Early Triassic or older, and the HO of phytosaurs is an Early Jurassic record. There is no compelling evidence of tetrapod mass extinctions at either the Carnian-Norian or the Triassic-Jurassic boundaries.
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Tetrapod footprints - their use in biostratigraphy and biochronology of the Triassic
Geological Society London Special Publications, 2010Co-Authors: Hendrik Klein, Spencer G. LucasAbstract:Triassic tetrapod footprints have a Pangaea-wide distribution; they are known from North America, South America, Europe, North Africa, China, Australia, Antarctica and South Africa. They often occur in sequences that lack well-preserved body fossils. Therefore, the question arises, how well can tetrapod footprints be used in age determination and correlation of stratigraphic units? The single largest problem with Triassic footprint biostratigraphy and biochronology is the nonuniform ichnotaxonomy and evaluation of footprints that show extreme variation in shape due to extramorphological (substrate-related) phenomena. Here, we exclude most of the countless ichnospecies of Triassic footprints, and instead we consider ichnogenera and form groups that show distinctive, anatomically-controlled features. Several characteristic footprint assemblages and ichnotaxa have a restricted stratigraphic range and obviously occur in distinct time intervals. This can be repeatedly observed in the global record. Some reflect distinct stages in the evolutionary development of the locomotor apparatus as indicated by their digit proportions and the trackway patterns. Essential elements are archosaur tracks with Rotodactylus, the chirotherian ichnotaxa Protochirotherium, Synaptichnium, Isochirotherium, Chirotherium and Brachychirotherium, and grallatorids that can be partly linked in a functional-evolutionary sequence. Non-archosaur footprints are common, especially the ichnotaxa Rhynchosauroides, Procolophonichnium, Capitosauroides and several dicynodont-related or mammal-like forms. They are dominant in some footprint assemblages. From the temporal distribution pattern we recognize five distinct tetrapod-footprint-based biochrons likened to the known land-vertebrate faunachrons (LVFs) of the tetrapod body fossil record: 1. Dicynodont tracks (Lootsbergian 1⁄4 Induan age); 2. Protochirotherium (Synaptichnium), Rhynchosauroides, Procolophonichnium (Nonesian 1⁄4 Induan–Olenekian age); 3. Chirotherium barthii, C. sickleri, Isochirotherium, Synaptichnium (‘Brachychirotherium’), Rotodactylus, Rhynchosauroides, Procolophonichnium, dicynodont tracks, Capitosauroides (Nonesian– Perovkan 1⁄4 Olenekian–early Anisian); 4. Atreipus–Grallator (‘Coelurosaurichnus’), Synaptichnium (‘Brachychirotherium’), Isochirotherium, Sphingopus, Parachirotherium, Rhynchosauroides, Procolophonichnium (Perovkan–Berdyankian 1⁄4 Late Anisian–Ladinian); 5. Brachychirotherium, Atreipus–Grallator, Grallator, Eubrontes, Apatopus, Rhynchosauroides, dicynodont tracks (Otischalkian–Apachean 1⁄4 Carnian–Rhaetian). Tetrapod footprints are useful for biostratigraphy and biochronology of the Triassic. However, compared to the tetrapod body fossil record with eight biochrons, the five footprint-based biochrons show less resolution of faunal turnover as ichnogenera and ichnospecies at best reflect biological families or higher biotaxonomic units. Nevertheless, in sequences where body fossils are rare, footprints can coarsely indicate their stratigraphic age. Tetrapod footprints of Triassic age are known from North America, South America, Europe, North Africa, China, Australia, Antarctica and South Africa (Figs 1 & 2). The Triassic footprint record is archosaur-, lepidosauromorph/ archosauromorph(Rhynchosauroides) and synapsiddominated (Haubold 1971b, 1984; Klein & Haubold 2007), and it includes the oldest dinosaur tracks. Much has been written about Triassic tetrapod footprint biostratigraphy, especially based on the European and North American records (see below). Our goal here is to present a Pangaea-wide Triassic biostratigraphy and biochronology based on tetrapod footprints. To do so, we briefly discuss some problems of footprint ichnotaxonomy and their bearing on footprint biostratigraphy (see Lucas 2007 for a more extensive review of these issues). We follow with a review of the principal Triassic tetrapod footprint assemblages. We conclude with a synopsis of Triassic tetrapod footprint biochronology that recognizes five biochrons and compare that biochronology to Triassic tetrapod biochronology based on body fossils. From: LUCAS, S. G. (ed.) The Triassic Timescale. Geological Society, London, Special Publications, 334, 419–446. DOI: 10.1144/SP334.14 0305-8719/10/$15.00 # The Geological Society of London 2010. Fig. 1. Distribution of principal Triassic tracksites on Triassic Pangaea. Locations are: 1, Sydney basin, Australia; 2, Karoo basin, South Africa; 3, Antarctica; 4, western Europe, 5, Italy; 6, Chinle basin, western United States; 7, Newark basin, New Jersey; 8, Argentina; and 9, Yangtze basin, China. Base map after Wing & Sues (1992). Fig. 2. Principal Triassic footprint horizons and footprint localities. German section and numerical age according to Menning & German Stratigraphic Commission (2002) and Bachmann & Kozur (2004). H. KLEIN & S. G. LUCAS 420
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The Triassic timescale based on nonmarine tetrapod biostratigraphy and biochronology
Geological Society London Special Publications, 2010Co-Authors: Spencer G. LucasAbstract:Abstract The Triassic timescale based on nonmarine tetrapod biostratigraphy and biochronology divides Triassic time into eight land-vertebrate faunachrons (LVFs) with boundaries defined by the first appearance datums (FADs) of tetrapod genera or, in two cases, the FADs of a tetrapod species. Definition and characterization of these LVFs is updated here as follows: the beginning of the Lootsbergian LVF=FAD of Lystrosaurus ; the beginning of the Nonesian=FAD Cynognathus ; the beginning of the Perovkan LVF=FAD Eocyclotosaurus ; the beginning of the Berdyankian LVF=FAD Mastodonsaurus giganteus ; the beginning of the Otischalkian LVF=FAD Parasuchus ; the beginning of the Adamanian LVF=FAD Rutiodon ; the beginning of the Revueltian LVF=FAD Typothorax coccinarum ; and the beginning of the Apachean LVF=FAD Redondasaurus . The end of the Apachean (= beginning of the Wasonian LVF, near the beginning of the Jurassic) is the FAD of the crocodylomorph Protosuchus . The Early Triassic tetrapod LVFs, Lootsbergian and Nonesian, have characteristic tetrapod assemblages in the Karoo basin of South Africa, the Lystrosaurus assemblage zone and the lower two-thirds of the Cynognathus assemblage zone, respectively. The Middle Triassic LVFs, Perovkan and Berdyankian, have characteristic assemblages from the Russian Ural foreland basin, the tetrapod assemblages of the Donguz and the Bukobay svitas, respectively. The Late Triassic LVFs, Otischalkian, Adamanian, Revueltian and Apachean, have characteristic assemblages in the Chinle basin of the western USA, the tetrapod assemblages of the Colorado City Formation of Texas, Blue Mesa Member of the Petrified Forest Formation in Arizona, and Bull Canyon and Redonda formations in New Mexico. Since the Triassic LVFs were introduced, several subdivisions have been proposed: Lootsbergian can be divided into three sub-LVFs, Nonesian into two, Adamanian into two and Revueltian into three. However, successful inter-regional correlation of most of these sub-LVFs remains to be demonstrated. Occasional records of nonmarine Triassic tetrapods in marine strata, palynostratigraphy, conchostracan biostratigraphy, magnetostratigraphy and radioisotopic ages provide some basis for correlation of the LVFs to the standard global chronostratigraphic scale. These data indicate that Lootsbergian=uppermost Changshingian, Induan and possibly earliest Olenekian; Nonesian=much of the Olenekian; Perovkan=most of the Anisian; Berdyankian=latest Anisian? and Ladinian; Otischalkian=early to late Carnian; Adamanian=most of the late Carnian; Revueltian=early–middle Norian; and Apachean=late Norian–Rhaetian. The Triassic timescale based on tetrapod biostratigraphy and biochronology remains a robust tool for the correlation of nonmarine Triassic tetrapod assemblages independent of the marine timescale.
Jonathan L. Payne - One of the best experts on this subject based on the ideXlab platform.
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factors controlling carbonate platform asymmetry preliminary results from the great bank of guizhou an isolated permian Triassic platform in the nanpanjiang basin south china
Palaeogeography Palaeoclimatology Palaeoecology, 2012Co-Authors: Daniel J Lehrmann, Jonathan L. Payne, Brian M Kelley, Marcello MinzoniAbstract:Abstract A well-exposed isolated carbonate platform, the Great Bank of Guizhou, in the Nanpanjiang Basin of south China, developed from the latest Permian to the earliest Late Triassic. Platform strata are dissected by a faulted syncline exposing a complete cross section through the interior, margins and flanks, enabling a detailed assessment of depositional controls. Previous studies portrayed the platform as having a relatively symmetrical architecture even though much of the former work was focused on the platform interior and northern margin–basin transition. Our research reveals five aspects of the southern margin facies and stratigraphy that are significantly different from those of the northern margin: (1) subaerial exposure and unconformity developed on top of the Upper Permian sponge boundstone and in the overlying Lower Triassic strata; (2) Permian and Triassic clasts chaotically admixed within Early Triassic breccias; (3) Lower Triassic strata remarkably thinner on the southern margin; (4) a much narrower Tubiphytes reef facies preserved along the southern margin in the Middle Triassic; and (5) large scallop shaped reentrants at the southern margin evident in satellite images. Three end-member models may explain the asymmetry: (1) antecedent topography of the underlying Upper Permian reef-rimmed margin coupled with eustatic sea level fluctuation; (2) differential tectonic uplift; and (3) large-scale submarine collapse of the platform margin. Subaerial exposure and admixing of Permian and Triassic clasts observed at Yungan section is best explained by the tectonic uplift model. However, the submarine collapse model also explains several of the observations if it is associated with uplift(s) or sea level fall(s). Submarine collapse is supported by large concave erosional reentrants (scallops) visible in satellite images. Taken together, our observations suggest that a combination of tectonic uplift and margin collapse contributed to platform asymmetry. Further work promises to further constrain the details and timing of processes that contributed to the asymmetry.
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early and middle Triassic trends in diversity evenness and size of foraminifers on a carbonate platform in south china implications for tempo and mode of biotic recovery from the end permian mass extinction
Paleobiology, 2011Co-Authors: Jonathan L. Payne, Demir Altiner, Mindi M Summers, Brianna L Rego, Jiayong Wei, Daniel J LehrmannAbstract:Delayed biotic recovery from the end-Permian mass extinction has long been interpreted to result from environmental inhibition. Recently, evidence of more rapid recovery has begun to emerge, suggesting the role of environmental inhibition was previously overestimated. However, there have been few high-resolution taxonomic and ecological studies spanning the full Early and Middle Triassic recovery interval, leaving the precise pattern of recovery and underlying mechanisms poorly constrained. In this study, we document Early and Middle Triassic trends in taxonomic diversity, assemblage evenness, and size distribution of benthic foraminifers on an exceptionally exposed carbonate platform in south China. We observe gradual increases in all metrics through Early Triassic and earliest Middle Triassic time, with stable values reached early in the Anisian. There is little support in our data set for a substantial Early Triassic lag interval during the recovery of foraminifers or for a stepwise recovery pattern. The recovery pattern of foraminifers on the GBG corresponds well with available global data for this taxon and appears to parallel that of many benthic invertebrate clades. Early Triassic diversity increase in foraminifers was more gradual than in ammonoids and conodonts. However, foraminifers continued to increase in diversity, size, and evenness into Middle Triassic time, whereas diversity of ammonoids and conodonts declined. These contrasts suggest decoupling of recovery between benthic and pelagic environments; it is unclear whether these discrepancies reflect inherent contrasts in their evolutionary dynamics or the differential impact of Early Triassic ocean anoxia or associated environmental parameters on benthic ecosystems.
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Evidence for recurrent Early Triassic massive volcanism from quantitative interpretation of carbon isotope fluctuations
Earth and Planetary Science Letters, 2007Co-Authors: Jonathan L. Payne, Lee R. KumpAbstract:Abstract Carbon cycle disturbance associated with mass extinction at the end of the Permian Period continued through the Early Triassic, an interval of approximately 5 million years. Coincidence of carbon cycle stabilization with accelerated Middle Triassic biotic recovery suggests a link between carbon cycling and biodiversity, but the cause of Early Triassic carbon isotope excursions remains poorly understood. Previous modeling studies have focused exclusively on the initial negative excursion in δ13C across the Permian–Triassic boundary and have not addressed the cycles of positive and negative excursions observed through the Early Triassic. This study uses a simple carbon cycle box model to investigate potential causes underlying the series of Early Triassic carbon isotope excursions and to assess possible relationships between isotope excursions and coeval patterns of carbonate deposition. According to the model, introduction of carbon with the isotope composition of volcanic CO2 produces small negative carbon isotope excursions followed by larger and more protracted positive excursions. Positive excursions result because increased pCO2 causes warming, enhancing marine anoxia and associated regeneration of phosphate and thus allowing greater productivity. In addition, carbonate weathering is more sensitive than organic carbon weathering to changes in atmospheric pCO2 and climate, causing an increase in the overall δ13C composition of weathered carbon. Therefore, the full Early Triassic record of negative and positive carbon isotope excursions can only be accounted for within the model by several pulses of carbon release characterized by varying mixtures of organic and mantle isotope compositions. Thermal metamorphism of coal and carbonate rocks in the crust of the Siberian craton during eruption of the Siberian Traps flood basalts provides the most plausible mechanism for such a carbon release scenario. If multiple episodes of CO2 release account for Early Triassic carbon cycle instability (regardless of their precise trigger), then cessation of CO2 release is likely to explain acceleration of biotic recovery early in the Middle Triassic.
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evolutionary dynamics of gastropod size across the end permian extinction and through the Triassic recovery interval
Paleobiology, 2005Co-Authors: Jonathan L. PayneAbstract:Abstract A global database of gastropod sizes from the Permian through the Middle Triassic documents trends in gastropod shell size and permits tests of the suggestion that Early Triassic gastropods were everywhere unusually small. Analysis of the database shows that no specimens of unambiguous Early Triassic age larger than 2.6 cm have been reported, in contrast to common 5– 10-cm specimens of both Permian and Middle Triassic age. The loss of large gastropods is abrupt even at a fine scale of stratigraphic resolution, whereas the return of larger individuals in the Middle Triassic appears gradual when finely resolved. Taphonomic and sampling biases do not adequately explain the absence of large Early Triassic gastropods. Examination of size trends by genus demonstrates that the size decrease across the Permian/Triassic boundary is compatible with both size-selective extinction at the species level and anagenetic size change within lineages. Size increase in the Middle Triassic resulted from the originati...
