Latest Permian Extinction Research Articles

Continental weathering and recovery from ocean nutrient stress during the Early Triassic Biotic Crisis

Following the latest Permian extinction ∼252 million years ago, normal marine and terrestrial ecosystems did not recover for another 5-9 million years. The driver(s) for the Early Triassic biotic crisis, marked by high atmospheric CO2 concentration, extreme ocean warming, and marine anoxia, remains unclear. Here we constrain the timing of authigenic K-bearing mineral formation extracted from supergene weathering profiles of NW-Pangea by Argon geochronology, to demonstrate that an accelerated hydrological cycle causing intense chemical alteration of the continents occurred between ∼254 and 248 Ma, and continued throughout the Triassic period. We show that enhanced ocean nutrient supply from this intense continental weathering did not trigger increased ocean productivity during the Early Triassic biotic crisis, due to strong thermal ocean stratification off NW Pangea. Nitrogen isotope constraints suggest, instead, that full recovery from ocean nutrient stress, despite some brief amelioration ∼1.5 million years after the latest Permian extinction, did not commence until climate cooling revitalized the global upwelling systems and ocean mixing ∼10 million years after the mass extinction.

Microbial Blooms Triggered Pyrite Framboid Enrichment and Oxygen Depletion in Carbonate Platforms Immediately After the Latest Permian Extinction

AbstractRedox variations across the Permian‐Triassic boundary (PTB) have long been debated, especially during the proliferation of PTB microbialites. Here, we report redox fluctuations across the PTB to evaluate links between the two based on pyrite framboid analysis from basin to platform settings in South China. During the end‐Permian extinction, abundant framboids indicate a widespread anoxia that was likely a direct cause of extinction. In the earliest Triassic (Hindeodus parvus conodont zone), pyrite framboids were absent in ramp to basin and shallow, nonmicrobialite platform sections. In contrast, the coeval microbialites yield abundant framboids indicative of dysoxia. The fact that framboids were only confined to PTB microbialites and absent in other habitats indicates that microbe bloom may have stimulated dysoxic watermass and triggered the framboid growth within microbe aggregates. Thus, microbialites were not built in reducing settings, but instead, microbial proliferation caused local, dysoxia within shallow oxygenated platforms after the extinction.

Toxic mercury pulses into late Permian terrestrial and marine environments

Abstract Large spikes in mercury (Hg) concentration are observed globally at the latest Permian extinction (LPE) horizon that are thought to be related to enhanced volcanic emissions of the Siberian Traps large igneous province (LIP). While forming an effective chemostratigraphic marker, it remains unclear whether such enhanced volcanic Hg emissions could have generated toxic conditions that contributed to extinction processes. To address this, we examined the nature of enhanced Hg emissions from the Siberian Traps LIP and the potential impact it may have had on global ecosystems during the LPE. Model results for a LIP eruption predict that pulses of Hg emissions to the atmosphere would have been orders of magnitude greater than normal background conditions. When deposited into world environments, this would have generated a series of toxic shocks, each lasting >1000 yr. Such repeated Hg loading events would have had severe impact across marine trophic levels, as well as been toxic to terrestrial plant and animal life. Such high Hg loading rates may help explain the co-occurrence of marine and terrestrial extinctions.

New Stage of Recovery of East European Tetrapod Community after Permian–Triassic Crisis

New data on the taxonomic composition and comparison of the tetrapod assemblage from the Upper Sukhorechenskaya Subformation of the Buzuluk Depression of the East European Platform, previously described as “Selenocara–Syrtosuchus fauna,” are provided. This assemblage is dated Late Induan (Dienerian) and characterizes a new stage in recovery of East European tetrapod community after the Late Permian extinction, which is intermediate between the Tupilakosaurus and Benthosuchus faunas. Beyond Eastern Europe, a similar amphibian association is known from the Anodontophora fassaensis Zone (upper part of the Wordie Creek Formation) of eastern Greenland.

Permian-Triassic Charophytes: Distribution, Biostratigraphy and Biotic Events

Permian charophytes are known from the Ukraine, Russia, Kazakhstan, Germany, Saudi Arabia, China, the USA, Brazil, Paraguay and India. Most of these records are of Middle- Late Permian Age and are the basis of local biostratigraphic zonation in southern Russia and China. Development of a robust Permian charophyte biostratigraphy will require a more extensive record. Triassic charophytes are known from Germany, Sweden, Poland, Slovenia, Bulgaria, the Ukraine, Russia, Morocco, Congo, the USA, Argentina, Kazakhstan and China. This encompasses records from all Triassic stages and has been the basis of detailed biostratigraphic zonation in southern Russia-Kazakhstan-eastern Europe. Permian and Triassic charophyte biostratigraphy at the level of genus does not provide detailed correlations beyond local or regional schemes. Nevertheless, it does identify some important evolutionary datums that constrain the timing of important biotic events in the Permian-Triassic evolutionary history of the Charophyta, including: (1) Early Permian extinction of the Palaeocharaceae; (2) Late Permian extinction of the “Trochiliscales” (Moellerinales); (3) Carboniferous origin of the paraphyletic Porocharaceae, soon followed during the Permian by the origin of the multicellular basal plate; and (4) an important generic turnover of charophytes across the Triassic-Jurassic boundary, though there are insufficient data to identify this as a mass extinction.

Late Permian to Early Triassic changes in acritarch assemblages and morphology in the Boreal Arctic: New data from the Finnmark Platform

The Late Permian extinction interval is in many marine locations characterized by the development of anoxic conditions. The Finnmark Platform is one of few exceptions, as sedimentological and palynofacies evidence indicate oxygenated conditions throughout the event. Changes in acritarch assemblages and morphology were studied in order to better understand the link between acritarchs and environmental conditions. The main taxa are of Micrhystridium, Baltisphaeridium and leiospheres, while Veryhachium and the prasinophytes Cymatiosphaera and Tasmanites were present in low abundances. Increased concentrations of acritarchs, particularly Micrhystridium, show that the environmental changes at the start of the extinction event may have resulted in enhanced marine productivity. A shift from Micrhystridium/Baltisphaeridium dominance before and during the extinction event, to leiosphere-dominance after the extinction event, indicates a shift towards a more inshore environment. The new data are compared with published Late Permian acritarch records from East Greenland, China and Pakistan. A striking difference between the East Greenland and Finnmark Platform, which are both expanded Upper Permian/Lower Triassic sections, is that the acritarch record from Greenland shows a strong decrease in process length of the acritarch Micrhystridium. Together with a change in the acritarch assemblage, this change in morphology was interpreted to represent a decrease in salinity at the site, resulting from increased run-off. The differences between the East Greenland and the Finnmark records are likely due to their palaeogeographical settings, as the East Greenland section was located in a narrow and elongated basin which was likely more sensitive to evaporation and run-off changes than the Finnmark Platform.

Salinity changes and anoxia resulting from enhanced run-off during the late Permian global warming and mass extinction event

Abstract. The late Permian biotic crisis had a major impact on marine and terrestrial environments. Rising CO2 levels following Siberian Trap volcanic activity were likely responsible for expanding marine anoxia and elevated water temperatures. This study focuses on one of the stratigraphically most expanded Permian–Triassic records known, from Jameson Land, East Greenland. High-resolution sampling allows for a detailed reconstruction of the changing environmental conditions during the extinction event and the development of anoxic water conditions. Since very little is known about how salinity was affected during the extinction event, we especially focus on the aquatic palynomorphs and infer changes in salinity from changes in the assemblage and morphology. The start of the extinction event, here defined by a peak in spore : pollen, indicating disturbance and vegetation destruction in the terrestrial environment, postdates a negative excursion in the total organic carbon, but predates the development of anoxia in the basin. Based on the newest estimations for sedimentation rates, the marine and terrestrial ecosystem collapse took between 1.6 and 8 kyr, a much shorter interval than previously estimated. The palynofacies and palynomorph records show that the environmental changes can be explained by enhanced run-off and increased primary productivity and water column stratification. A lowering in salinity is supported by changes in the acritarch morphology. The length of the processes of the acritarchs becomes shorter during the extinction event and we propose that these changes are evidence for a reduction in salinity in the shallow marine setting of the study site. This inference is supported by changes in acritarch distribution, which suggest a change in palaeoenvironment from open marine conditions before the start of the extinction event to more nearshore conditions during and after the crisis. In a period of sea-level rise, such a reduction in salinity can only be explained by increased run-off. High amounts of both terrestrial and marine organic fragments in the first anoxic layers suggest that high run-off, increased nutrient availability, possibly in combination with soil erosion, are responsible for the development of anoxia in the basin. Enhanced run-off could result from changes in the hydrological cycle during the late Permian extinction event, which is a likely consequence of global warming. In addition, vegetation destruction and soil erosion may also have resulted in enhanced run-off. Salinity stratification could potentially explain the development of anoxia in other shallow marine sites. The input of freshwater and related changes in coastal salinity could also have implications for the interpretation of oxygen isotope records and seawater temperature reconstructions at some sites.

The fungal and acritarch events as time markers for the latest Permian mass extinction: An update

The latest Permian extinction (252 Myr ago) was the most severe in the geologic record. On land, widespread Late Permian gymnosperm/seed-fern dominated forests appear to have suffered rapid and almost complete destruction, as evidenced by increased soil erosion and changes in fluvial style in deforested areas, signs of wildfires, replacement of trees by lower plants, and almost complete loss of peat-forming and fire-susceptible vegetation. Permian–Triassic boundary strata at many sites show two widespread palynological events in the wake of the forest destruction: The fungal event, evidenced by a thin zone with >95% fungal cells (Reduviasporonites) and woody debris, found in terrestrial and marine sediments, and the acritarch event, marked by the sudden flood of unusual phytoplankton in the marine realm. These two events represent the global temporary explosive spread of stress-tolerant and opportunistic organisms on land and in the sea just after the latest Permian disaster. They represent unique events, and thus they can provide a time marker in correlating latest Permian marine and terrestrial sequences.

Permian tetrapod biochronology, correlation and evolutionary events

Abstract The most extensive Permian tetrapod (amphibian and reptile) fossil records from the western USA (New Mexico to Texas) and South Africa have been used to define 11 land vertebrate faunachrons (LVFs). These are, in ascending order, the Coyotean, Seymouran, Mitchellcreekian, Redtankian, Littlecrotonian, Kapteinskraalian, Gamkan, Hoedemakeran, Steilkransian, Platbergian and Lootsbergian. These faunachrons provide a biochronological framework with which to assign ages to, and correlate, Permian tetrapod fossil assemblages. Intercalated marine strata, radioisotopic ages and magnetostratigraphy were used to correlate the Permian LVFs to the standard global chronostratigraphic scale with varying degrees of precision. Such correlations identified the following significant events in Permian tetrapod evolution: a Coyotean chronofaunal event (end Coyotean); Redtankian events (Mitchellcreekian–Littlecrotonian); Olson's gap (late Littlecrotonian); a therapsid event (Kapteinskraalian); a dinocephalian extinction event (end Gamkan); and a latest Permian extinction event (Platbergian–Lootsbergian boundary). Problems of incompleteness, endemism and taxonomy, and the relative lack of non-biochronological age control continue to hinder the refinement and correlation of a Permian timescale based on tetrapod biochronology. Nevertheless, the global Permian timescale based on tetrapod biochronology is a robust tool for both global and regional age assignment and correlation. Advances in Permian tetrapod biochronology will come from new fossil discoveries, more detailed biostratigraphy and additional alpha taxonomic studies based on sound evolutionary taxonomic principles.

Isotopic signatures of mercury contamination in latest Permian oceans

Abstract Sedimentary records from the northwest margin of Pangea and the Tethys show anomalously high Hg levels at the latest Permian extinction boundary. Background δ202Hg values are consistent with normal marine conditions but exhibit negative shifts coincident with increased Hg concentrations. Hg isotope mass-independent fractionation (Δ199Hg) trends are consistent with volcanic input in deep-water marine environments. In contrast, nearshore environments have Δ199Hg signatures consistent with enhanced soil and/or biomass input. We hypothesize that the deep-water signature represents an overall global increase in volcanic Hg input and that this isotope signature is overwhelmed in nearshore locations due to Hg from terrestrial sources. High-productivity nearshore regions may have experienced stressed marine ecosystems due to enhanced Hg loading.

Early Triassic productivity crises delayed recovery from world’s worst mass extinction

Abstract The recovery of life after the latest Permian extinction was protracted over Early Triassic time. Detailed geochemistry of marine sections along northwest Pangea indicates that upwelling ceased at the extinction event. Nitrogen stable isotope data suggest that this was associated with progressive increase in nutrient stress throughout the Early Triassic, coincident with a significant decrease in organic carbon content despite pervasive anoxic to euxinic conditions. We argue that the Early Triassic hothouse both reduced marine productivity and deepened the nutricline, reducing the overall rate of nutrient delivery to the photic zone, creating an Early Triassic nutrient gap. When oceans finally cooled by Middle Triassic time, renewed nutrient upwelling and onset of organic-rich shale deposition occurred across northwest Pangea, marking the final return of global marine productivity.

Mercury anomalies associated with three extinction events (Capitanian Crisis, Latest Permian Extinction and the Smithian/Spathian Extinction) in NW Pangea

AbstractStrata of Permian – Early Triassic age that include a record of three major extinction events (Capitanian Crisis, Latest Permian Extinction and the Smithian/Spathian Extinction) were examined at the Festningen section, Spitsbergen. Over thec. 12 Ma record examined, mercury in the sediments shows relatively constant background values of 0.005–0.010 μg g–1. However, there are notable spikes in Hg concentration over an order of magnitude above background associated with the three extinctions. The Hg/total organic carbon (TOC) ratio shows similar large spikes, indicating that they represent a true increase in Hg loading to the environment. We argue that these represent Hg loading events associated with enhanced Hg emissions from large igneous province (LIP) events that are synchronous with the extinctions. The Hg anomalies are consistent across the NW margin of Pangea, indicating that widespread mercury loading occurred. While this provides utility as a chemostratigraphic marker the Hg spikes may also indicate loading of toxic metals to the environment, a contributing cause to the mass extinction events.

Integrated Sr isotope variations and global environmental changes through the Late Permian to early Late Triassic

New 87Sr/86Sr data based on 127 well-preserved and well-dated conodont samples from South China were measured using a new technique (LA-MC-ICPMS) based on single conodont albid crown analysis. These reveal a spectacular climb in seawater 87Sr/86Sr ratios during the Early Triassic that was the most rapid of the Phanerozoic. The rapid increase began in Bed 25 of the Meishan section (GSSP of the Permian–Triassic boundary, PTB), and coincided closely with the latest Permian extinction. Modeling results indicate that the accelerated rise of 87Sr/86Sr ratios can be ascribed to a rapid increase (>2.8×) of riverine flux of Sr caused by intensified weathering. This phenomenon could in turn be related to an intensification of warming-driven runoff and vegetation die-off. Continued rise of 87Sr/86Sr ratios in the Early Triassic indicates that continental weathering rates were enhanced >1.9 times compared to those of the Late Permian. Continental weathering rates began to decline in the middle–late Spathian, which may have played a role in the decrease of oceanic anoxia and recovery of marine benthos. The 87Sr/86Sr values decline gradually into the Middle Triassic to an equilibrium values around 1.2 times those of the Late Permian level, suggesting that vegetation coverage did not attain pre-extinction levels thereby allowing higher runoff.

Progressive environmental deterioration in northwestern Pangea leading to the latest Permian extinction

Stratigraphic records from northwestern Pangea provide unique insight into global processes that occurred during the latest Permian extinction (LPE). We examined a detailed geochemical record of the Festningen section, Spitsbergen. A stepwise extinction is noted as: starting with (1) loss of carbonate shelly macrofauna, followed by (2) loss of siliceous sponges in conjunction with an abrupt change in ichnofabrics as well as dramatic change in the terrestrial environment, and (3) final loss of all trace fossils. We interpret loss of carbonate producers as related to shoaling of the lysocline in higher latitudes, in relationship to building atmospheric CO2. The loss of siliceous sponges is coincident with the global LPE event and is related to onset of high loading rates of toxic metals (Hg, As, Co) that we suggest are derived from Siberian Trap eruptions. The final extinction stage is coincident with redox-sen- sitive trace metal and other proxy data that suggest onset of anoxia after the other extinction events. These results show a remarkable record of progressive environmental deterioration in northwestern Pangea during the extinction crises.

Contrasting geochemical signatures on land from the Middle and Late Permian extinction events

AbstractThe end of the Palaeozoic is marked by two mass‐extinction events during the Middle Permian (Capitanian) and the Late Permian (Changhsingian). Given similarities between the two events in geochemical signatures, such as large magnitude negative δ13C anomalies, sedimentological signatures such as claystone breccias, and the approximate contemporaneous emplacement of large igneous provinces, many authors have sought a common causal mechanism. Here, a new high‐resolution continental record of the Capitanian event from Portal Mountain, Antarctica, is compared with previously published Changhsingian records of geochemical signatures of weathering intensity and palaeoclimatic change. Geochemical means of discriminating sedimentary provenance (Ti/Al, U/Th and La/Ce ratios) all indicate a common provenance for the Portal Mountain sediments and associated palaeosols, so changes spanning the Capitanian extinction represent changes in weathering intensity rather than sediment source. Proxies for weathering intensity chemical index of alteration, ∆W and rare earth element accumulation all decline across the Capitanian extinction event at Portal Mountain, which is in contrast to the increased weathering recorded globally at the Late Permian extinction. Furthermore, palaeoclimatic proxies are consistent with unchanging or cooler climatic conditions throughout the Capitanian event, which contrasts with Changhsingian records that all indicate a significant syn‐extinction and post‐extinction series of greenhouse warming events. Although both the Capitanian and Changhsingian event records indicate significant redox shifts, palaeosol geochemistry of the Changhsingian event indicates more reducing conditions, whereas the new Capitanian record of reduced trace metal abundances (Cr, Cu, Ni and Ce) indicates more oxidizing conditions. Taken together, the differences in weathering intensity, redox and the lack of evidence for significant climatic change in the new record suggest that the Capitanian mass extinction was not triggered by dyke injection of coal‐beds, as in the Changhsingian extinction, and may instead have been triggered directly by the Emeishan large igneous province or by the interaction of Emeishan basalts with platform carbonates.

Gas hydrate contribution to Late Permian global warming

Rapid gas hydrate release (the “clathrate gun” hypothesis) has been invoked as a cause for the rapid global warming and associated negative carbon isotope excursion observed during the Latest Permian Extinction (LPE). We modeled the stability of gas hydrates through a warming Middle to Late Permian world, considering three settings for methane reservoirs: 1) terrestrial hydrates, 2) hydrates on exposed continental shelves during glacial sea level drop, and 3) hydrates in deep marine settings. Model results show that terrestrial hydrates would rapidly destabilize over ∼400 ky after deglaciation for moderate heatflow (40 mW/m2), and more rapidly for higher heat flow values. Exposed continental shelves would lose hydrates even more rapidly, after being flooded due to loss of ice storage on land. These two major hydrate reservoirs would thus have destabilized during the Middle to Late Permian climate warming, well prior to the LPE event. However, they may have contributed to the >2‰ negative C-isotopic shift during the late Middle Permian. Deep marine hydrates would have remained stable until LPE time. Rapid warming of deep marine waters during this time could have triggered destabilization of this reservoir, however given the configuration of one super continent, Pangea, hydrate bearing continental slopes would have been less extensive than modern day. This suggests that any potential gas hydrate release would have had only a minor contributing impact to the runaway greenhouse during the Latest Permian extinction.

Adaptive strategies and environmental significance of lingulid brachiopods across the late Permian extinction

Linguliform brachiopods are traditionally considered a conservative group which seems to pass through the late Permian extinction without any significant loss and even appear to thrive immediately after the extinction peak. In the Southern Alps, lingulids are very common in the post-extinction Mazzin Member (early Induan) of the Werfen Formation. Sparse occurrences are also known in the overlying Siusi and Gastropod Oolite members (late Induan and early Olenekian in age respectively). The recent discovery of well preserved specimens from a pre-extinction bed of the Bellerophon Formation (Changhsingian) has permitted a detailed comparative analysis, mostly based on the interior characters, preserved in the lingulid succession from across the extinction beds. The following effects on the lingulid populations have been analyzed: i) change in taxonomic assessment; ii) adaptive strategies during the surviving and recovery phases; and iii) environmental proxy connected with the killing mechanisms of the late Permian extinction.The pre-extinction individuals belong to Lingularia? cf. smirnovae Biernat and Emig, a species that is characterized by large-sized shells with a short lophophoral cavity. The post-extinction populations belong to different species and, probably, even to a different genus. The first post-extinction population (early Induan), with small-sized shells and long lophophoral cavity, has been referred to Lingularia yini (Peng and Shi). It records the most severe effects of the late Permian extinction on the marine ecosystems. The late Induan–Olenekian Lingularia borealis (Bittner), with large sized shells and long lophophoral cavity, appears during the first phase of the Triassic biotic recovery.The main adaptive strategies of Lingularia yini, in comparison with the Permian species, include: i) shell miniaturization; ii) increasing of the lophophoral cavity surface (respiratory surface); and iii) increasing of shell width/length ratio. These modifications are interpreted as adaptations towards warming and hypoxia, two main killing mechanisms of the marine biota. The recovery species Lingularia borealis maintains a large lophophoral cavity, indicating an adaptation towards predominant low oxygenated bottom marine waters.The appearance and the great abundance of Lingularia yini in the Mazzin Member (early Induan) represent a proxy of dysaerobic conditions, which determined the appearance of the second phase of the Lilliput biota, characterized by the definitive disappearance of the rhynchonelliform brachiopods and calcareous algae in the Southern Alps.

Elevated pCO2 leading to Late Triassic extinction, persistent photic zone euxinia, and rising sea levels

The Late Triassic mass extinction event is the most severe global warming–related crisis to have affected important extant marine groups such as scleractinian corals, and offers potential insights into climate change scenarios. Here we present evidence from Chlorobi-derived biomarkers of episodic and persistent photic zone euxinia. From biomarkers and stable carbon isotopes, we present evidence of rapid mixing of atmospheric and oceanic carbon reservoirs. Global versus regional trends are resolved in kerogen organic matter type, carbonate δ13C, and bulk and pyrite δ34S. This suite of data demonstrates for the first time a comprehensive organic and stable isotope geochemical reconstruction of events leading up to the Late Triassic extinction event and its aftermath. The cascade of events prior to, during, and after the extinction is remarkably similar to those reported for the Late Permian extinction, the largest extinction event of the Phanerozoic. We predict that similar conditions will have occurred during all past episodes of rapid global warming and biotic crisis that are associated with similar rises in p CO2.

Molybdenum isotopic evidence for oxic marine conditions during the latest Permian extinction

The latest Permian extinction (LPE), ca. 252 Ma, represents the most severe extinction event in Earth's history. The cause is still debated, but widespread marine anoxic to euxinic (H2S rich) conditions, from deep to shallow water environments, are commonly suggested. As a proxy for marine oxygen levels, we analyzed δ98/95Mo of two LPE sections that represent a gradient in water depth on the northwest margin of Pangea. Results from deep-water slope environments show a large shift in δ98/95Mo values from −2.02・to +2.23・at the extinction horizon, consistent with onset of euxinic conditions. In contrast, sub-storm wave base shelf environments show little change in the molybdenum isotopic composition (−1.34・to +0.05・, indicating ongoing oxic conditions across the LPE. These results indicate that areas of the continental shelf of northwest Pangea underwent mass extinction under oxic conditions throughout the LPE event, and that shallow-water anoxia was therefore not a global phenomenon.

Chemostratigraphy indicates a relatively complete Late Permian to Early Triassic sequence in the western United States

Research Article| April 01, 2013 Chemostratigraphy indicates a relatively complete Late Permian to Early Triassic sequence in the western United States Matthew R. Saltzman; Matthew R. Saltzman * School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA *E-mail: saltzman.11@osu.edu. Search for other works by this author on: GSW Google Scholar Alexa R.C. Sedlacek Alexa R.C. Sedlacek School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA Search for other works by this author on: GSW Google Scholar Geology (2013) 41 (4): 399–402. https://doi.org/10.1130/G33906.1 Article history received: 31 Jul 2012 rev-recd: 10 Oct 2012 accepted: 11 Oct 2012 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Matthew R. Saltzman, Alexa R.C. Sedlacek; Chemostratigraphy indicates a relatively complete Late Permian to Early Triassic sequence in the western United States. Geology 2013;; 41 (4): 399–402. doi: https://doi.org/10.1130/G33906.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Although the latest Permian mass extinction and associated δ13C excursion are well documented from the Tethys Ocean, carbonate rocks preserving these events in the eastern Panthalassic Ocean (western Pangea) are unknown. We present δ13Ccarb from the Gerster and Thaynes (Permian and Triassic) Formations in the western United States and document a negative excursion with no evidence for major breaks in continuity. To further constrain the age of the δ13Ccarb excursion in the absence of index fossils, we analyzed the same samples for 87Sr/86Sr. When examining our new carbon and Sr data in the context of biostratigraphy and sequence stratigraphy, we conclude that parts of the western United States may preserve carbonate successions that span the latest Permian extinction. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.