Some recent mass extinction papers:
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Francisco J. RodrÃguez-Tovar, Christopher M. Lowery, Timothy J. Bralower, Sean P.S. Gulick & Heather L. Jones (2020)
Rapid macrobenthic diversification and stabilization after the end-Cretaceous mass extinction event.
Geology (advance online publication)
doi:
https://doi.org/10.1130/G47589.1DOI:
https://doi.org/10.1130/G47589.1https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G47589.1/588088/Rapid-macrobenthic-diversification-and Previous ichnological analysis at the Chicxulub impact crater, YucatÃn Peninsula, MÃxico (International Ocean Discovery Program [IODP]/International Continental Scientific Drilling Program [ICDP] Site M0077), showed a surprisingly rapid initial tracemaker community recovery after the end-Cretaceous (Cretaceous-Paleogene [K-Pg]) mass extinction event. Here, we found that full recovery was also rapid, with the establishment of a well-developed tiered community within ~700 k.y. Several stages of recovery were observed, with distinct phases of stabilization and diversification, ending in the development of a trace fossil assemblage mainly consisting of abundant Zoophycos, Chondrites, and Planolites, assigned to the Zoophycos ichnofacies. The increase in diversity is associated with higher abundance, larger forms, and a deeper and more complex tiering structure. Such rapid recovery suggests that favorable paleoenvironmental conditions were quickly reestablished within the impact basin, enabling colonization of the substrate. Comparison with the end-Permian extinction reveals similarities during recovery, yet postextinction recovery was significantly faster after the K-Pg event. The rapid recovery has significant implications for the evolution of macrobenthic biota after the K-Pg event. Our results have relevance in understanding how communities recovered after the K-Pg impact and how this event differed from other mass extinction events.
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News:
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Paul B. Wignall & Jed W. Atkinson (2020)
A two-phased end-Triassic mass extinction.
Earth-Science Reviews 103282 (advance online publication)
doi:
https://doi.org/10.1016/j.earscirev.2020.103282 https://www.sciencedirect.com/science/article/abs/pii/S0012825220303287The end-Triassic mass extinction was one of the big five crises of the fossil record. It affected diverse marine groups, including bivalves, brachiopods, ostracods, calcareous algae, radiolarians, and tetrapods and coincided with major changes in palynological assemblages. The rapidity of the event has long been debated and here we show that it can be resolved into two distinct, short-lived extinction pulses separated by a several hundred-thousand-year interlude phase. Detailed collecting in the British Isles shows the first extinction in the lower Cotham Member eliminated many bivalves and ostracods. This event has been previously considered as the end-Triassic mass extinction horizon, however a second extinction is also seen at the top of the Langport Member after a phase of recovery marked by diversity increase. This younger crisis caused the loss of further bivalves, ostracods and the last of the conodonts. The two phases of marine extinctions coincide with marked turnovers amongst palynofloral assemblages with the interlude phase manifest as a fern spore-dominated interval (the Polypodiisporites polymicroforatus abundance interval). Correlation of Triassic-Jurassic boundary sections (and their associated extinction record) in Europe has been controversial. The most parsimonious correlation scheme assumes that a brief, high amplitude negative excursion of Î13Corg values, seen at the level of the first extinction phase in the UK, is manifest in other European sections in the same way. Alternative correlation schemes require complex scenarios with extinction occurring in some areas as recovery is happening elsewhere. In Europe, the first extinction coincides with regression whilst the second occurs at a flooding surface marked by the spread of anoxia. The extinction history of the terminal Triassic crisis is remarkably similar to that seen during other extinction events (end-Ordovician, Permo-Triassic, Toarcian) and suggests that, if the ultimate driver of these crises â large igneous province eruptions â is the same, then they show the same "double-punch" eruption history separated by a more benign interval of a few hundred-thousand-year duration.
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Victoria A. Petryshyn, Sarah E. Greene, ÂAlex Farnsworth, Daniel J.Lunt, Anne Kelley, Robert Gammariello, Yadira Ibarra, David J. Bottjer, Aradhna Tripati & Frank A. Corsetti (2020)
The role of temperature in the initiation of the end-Triassic mass extinction.
Earth-Science Reviews 103266 (advance online publication)
doi:
https://doi.org/10.1016/j.earscirev.2020.103266 https://www.sciencedirect.com/science/article/abs/pii/S0012825220303123The end-Triassic mass extinction coincided with the eruption of the Central Atlantic Magmatic Province, a large igneous province responsible for the massive atmospheric input of potentially climate-altering volatile compounds that is associated with a sharp rise in atmospheric CO2. The extinction mechanism is debated, but both short-term cooling (~10s of years) related to sulfur aerosols and longer-term warming (10,000âyrs) related to CO2 emissions -- essentially opposite hypotheses -- are suggested triggers. Until now, no temperature records spanning this crucial interval were available to provide a baseline or to differentiate between hypothesized mechanisms. Here, we use clumped-isotope paleothermometry of shallow marine microbialites coupled with climate modeling to reconstruct ocean temperature at the extinction horizon. We find mild to warm ocean temperatures during the extinction event and evidence for repeated temperature swings of ~16âÂC, which we interpret as a signature of strong seasonality. These results constitute the oldest non-biomineralized marine seasonal temperature record. We resolve no apparent evidence for short-term cooling or initial warming across the 1-80kyr of the extinction event our record captures, implying that the initial onset of the biodiversity crisis may necessitate another mechanism.
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The end-Permian mass extinction (EPME) is regarded as the most severe biotic crisis in Earth history, which is particularly well-documented in the marine fossil record. Despite compelling evidence that dramatic global environmental changes probably drove this extinction event, its effects on terrestrial plants are still highly controversial. Here we present Changhsingian (latest Permian) to late Smithian (latest Early Triassic) composite palynological successions from the lagoonal to open marine Qubu and Tulong sections in southern Tibet. Quantitative analyses of palynomorph distributions (range charts and relative abundance data) allow us to differentiate five distinct, informal palynofloral assemblages in ascending order: the Scheuringipollenites ovatus--Vitreisporites pallidus (OP) assemblages, the Reduviasporonites catenulatus (Ð) assemblage, the Endosporites papillatus--Pinuspollenites thoracatus (PT) assemblages, the Lundbladispora brevicula--Densoisporites nejburgii (BN) assemblages and the Falcisporites nuthallensis--Alisporites landianus (NL) assemblages. These palynological assemblage intervals and the associated ammonoid and conodont biostratigraphy resolve vegetation changes across the PermianâTriassic boundary (PTB) on the northern Tethyan margin of Gondwanaland in great detail and high resolution. Principal Component Analysis (PCA) of palynological data indicates that the OP assemblages, which are dominated by non-taeniate bisaccate pollen, represent a vegetation in a cool and dry climate during the Changhsingian. In the Qubu Section, the palynological turnover from the OP assemblages to the C assemblage 0.81âm below the PTB, coincides with abrupt sea-level fluctuations in the latest Permian. As this turnover further coincides with an extreme negative Î13Corg shift, a great abundance of amorphous organic matter (AOM) and marine acritarchs as well as the frequent occurrence of Reduviasporonites catenulatus, the C assemblage is tentatively interpreted to represent the "fungal spike" reported worldwide at the onset of the EPME. In southern Tibet, the EPME appears to result only in a short-term disturbance and range contraction of land-plant communities. Surprisingly, the early Dienerian PT assemblages, postdating the EPME by about 500Kyrs, closely resemble the late Changhsingian OP assemblages, suggesting a resurgence of those land plant groups that were dominant during the late Changhsingian. This recovery was disrupted with the onset of the late Dienerian BN assemblages in the Qubu Section, which is represented by a peak abundance of cavate trilete spores, reflecting large-scale deforestation. For nearly one million years, the regional vegetation appears to have been dominated by pioneer communities of quillworts and spike mosses. Only towards the end of the Smithian, bisaccate gymnosperm pollen regained dominance with the onset of the NL assemblages in the Tulong Section. Integrating the results of the Principal Component Analysis on our new palynological data and conodont-apatite oxygen-isotope data from neighbouring sections in Pakistan, the contraction of gymnosperm forests during the early Dienerian-Smithian in southern Tibet is interpreted to be accompanied by an abrupt change to an episode with a warmer and more humid climate.
This observation supports the hypothesis that the secondary eruptions of the Siberian Large Igneous Province during the Induan led to long-term global warming and, as a side effect, to more humid conditions in the southern temperate zone as a result of altered precipitation and evaporation patterns.
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