THE IMPACT OF THE PERMO-TRIASSIC MASS EXTINCTION ON TERRESTRIAL AND MARINE BIOGEOGRAPHY

2019 ◽  
Author(s):  
Bethany J. Allen ◽  
◽  
Paul B. Wignall ◽  
Daniel J. Hill ◽  
Erin E. Saupe ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Marine Biogeography ◽  
The Impact

The Kara astrobleme size, age and potential paleo-ecological effects of the impact event (European Arctic Zone, Russia)

2021 ◽  
Author(s):  
Tatyana Shumilova
Keyword(s):  
Mass Extinction ◽  
Black Shales ◽  
Ecological Effects ◽  
Impact Event ◽  
Arctic Zone ◽  
Russian Science ◽  
Future Possibility ◽  
Impact Melt ◽  
European Arctic ◽  
The Impact

<p>The Kara astrobleme is one of the biggest meteoritic craters which is set at the Baydarata Bay of the Kara sea (European Arctic Zone, Russia). It is a result of the catastrophic impact event occurred close to the K/Т extinction. The Kara astrobleme is the largest European crater at the modern erosion level.  At present it is estimated with the diameter from rim to rim about 65 km. While, some scientists have proposed its larger initial size – up to 120 km diameter, but no any well presented proof has been provided for the hypothesis. In 2015-2019 we have provided wide geological observations at the Kara crater and the near-set Ust`-Kara area (UKA) impactites. We have found for the first time that the UKA impactites, described in earlier Russian scientists publications as a synchronic independent crater of the same bolide, can be presented with bottom-flow impactites from the Kara crater (Shumilova et al., 2020). The found bottom-flow impactites abundant with belt-like impact melt bodies enriched in coesite and liquation structures similar to the Kara UHPHT vein and vein-like melt bodies with UHPHT impact glasses. Thus, they belong to UHPHT impactites. According to our air-bird view observations and impactites outcrops description at the UKA we support the hypothesis of the larger Kara crater getting 100-120 km in diameter of the initially originated size. Such giant meteorite event should be followed by catastrophic effects at the planet level, such as mass extinction. The present accepted Kara impact event age followed by the most recent measurements by <sup>40</sup>Ar-<sup>39</sup>Ar method is equal to 70.3 ± 2.2 Ma (Trieloff et al., 1998), that is a bit earlier than the Cretaceous/Tertiary boundary (K/Т) mass extinction at 66 Ma. But, previously, Kara age has been proposed by 65.7 Ma as a probable K/T impact (Kolesnikov et al., 1988; Nazarov et al., 1992). According to different data, the Kara event age lies within the range from 60 to 81 Ma (Masaitis & Mashchak, 1982; Nazarov et al., 1989; Kolesniov et al., 1990; Koeberl et al., 1990). It is clear that the accuracy of the age measurements depend on the quality of the studied samples, including their crystallinity, velocity of impact melt cooling and alteration, and from the used type of a method. By the moment, we have found out “in situ” crystallized zircons within the just discovered real UHPHT impact melt glasses (Shumilova et al., 2018, 2020). The UHPHT glasses do not have any alteration, thus, they can be used for accurate age measurements. Taking a future possibility for more accurate age analysis in the nearest future we can propose a correct vision of the possibility of the giant Kara influence to K-T mass extinction or other ecological effects. In any case following to the giant size of the Kara event touched the sedimentary rocks abundant with black shales and carbonates, which should be a result of essential atmospheric changes. The study has been supported by the Russian Science Foundation project #17-17-01080.</p>

scholarly journals The impact of the Cretaceous–Paleogene (K–Pg) mass extinction event on the global sulfur cycle: Evidence from Seymour Island, Antarctica

2018 ◽  
Vol 230 ◽  
pp. 17-45 ◽  
Author(s):  
James D. Witts ◽  
Robert J. Newton ◽  
Benjamin J.W. Mills ◽  
Paul B. Wignall ◽  
Simon H. Bottrell ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Sulfur Cycle ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
The Impact ◽  
Seymour Island

Primary productivity, deoxygenation, and the Gulliver-absence effect determine bivalve body size following the end-Permian mass extinction

2020 ◽  
Author(s):  
Melanie Tietje ◽  
William J. Foster ◽  
Jana Gliwa ◽  
Clara Lembke ◽  
Autumn Pugh ◽  
...  
Keyword(s):  
Body Size ◽  
Ocean Circulation ◽  
Mass Extinction ◽  
The Body ◽  
Large Species ◽  
Mass Extinctions ◽  
Shell Size ◽  
Body Sizes ◽  
Permian Mass Extinction ◽  
The Impact

<p> The impact of mass extinctions on the body sizes of animals has received considerable attention and debate, as to whether the reduced size of post-extinction organisms is due to the selective extinction of large species, absence of large species as a stochastic effect of low-diversity faunas, or a size decrease within surviving genera and species. Here, we investigated the body sizes of bivalves following the end-Permian mass extinction event and show that the shell size increase of bivalve genera was driven by both evolutionary and ecophenotypic responses. First, some genera show significant increases in body size with the evolution of new species. Further, the same genera record significant within-species increases in average and maximum body size into the late Induan, indicating that ecophenotypic changes were also involved on long-term body size trends. These increases are associated with invigorated ocean circulation, improved oxygenation of the seafloor, and probably increased food supply.</p>

Quantifying the process and abruptness of the end-Permian mass extinction

Paleobiology ◽  
10.1666/13022 ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 113-129 ◽  
Author(s):  
Yue Wang ◽  
Peter M. Sadler ◽  
Shu-zhong Shen ◽  
Douglas H. Erwin ◽  
Yi-chun Zhang ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Statistical Treatment ◽  
Catastrophic Event ◽  
Optimal Sequence ◽  
Data Set ◽  
Meishan Section ◽  
Biotic Recovery ◽  
Biodiversity Pattern ◽  
Permian Mass Extinction ◽  
The Impact

Studies of the end-Permian mass extinction have suggested a variety of patterns from a single catastrophic event to multiple phases. But most of these analyses have been based on fossil distributions from single localities. Although single sections may simplify the interpretation of species diversity, they are susceptible to bias from stratigraphic incompleteness and facies control of preservation. Here we use a data set of 1450 species from 18 fossiliferous sections in different paleoenvironmental settings across South China and the northern peri-Gondwanan region, and integrate it with high-precision geochronologic data to evaluate the rapidity of the largest Phanerozoic mass extinction. To reduce the Signor-Lipps effect, we applied constrained optimization (CONOP) to search for an optimal sequence of first and last occurrence datums for all species and generate a composite biodiversity pattern based on multiple sections. This analysis indicates that an abrupt extinction of 62% of species took place within 200 Kyr. The onset of the sudden extinction is around 252.3 Ma, just below Bed 25 at the Meishan section. Taxon turnover and diversification rates suggest a deterioration of the living conditions nearly 1.2 Myr before the sudden extinction. The magnitude of the extinction was such that there was no immediate biotic recovery. Prior suggestions of highly variable, multi-phased extinction patterns reflect the impact of the Signor-Lipps effect and facies-dependent occurrences, and are not supported following appropriate statistical treatment of this larger data set.

scholarly journals Evidence for fungal proliferation following the Cretaceous/Paleogene mass-extinction event, based on chemostratigraphy in the Raton and Powder River basins, western North America

2020 ◽  
pp. 134-142
Author(s):  
Keith Berry
Keyword(s):  
Amino Acid ◽  
North America ◽  
Mass Extinction ◽  
River Basins ◽  
High Energy ◽  
Western North America ◽  
Ecosystem Recovery ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
The Impact

The presence of the amino acid α-aminoisobutyric acid (Aib) within Cretaceous/Paleogene (K/Pg) boundary clay in the Raton and Powder River basins in Colorado and Wyoming, respectively, has been described as compelling evidence that extraterrestrial Aib survived the high-energy Chicxulub impact. Based on contemporary experiments and simulations, however, it is highly unlikely that extraterrestrial Aib survived the impact, which had peak impact pressures and temperatures in excess of 600 GPa and 10,000 K, respectively. In other words, the amino acid signature of the carbonaceous chondritic asteroid that impacted Chicxulub was undoubtedly destroyed upon impact during formation of the vapor plume or so-called “fireball.” The only organisms known to produce Aib are the suite (more than 30 genera) of cosmopolitan saprotrophic filamentous fungi that include Trichoderma Pers., which has recently been hypothesized to have thrived during the K/Pg mass-extinction event. Therefore it is proposed that the Aib horizon in the K/Pg boundary clay in the Raton and Powder River basins correlates with the K/Pg boundary fungal spike, which thus far has only been observed in New Zealand (Southern Hemisphere). This proposition is based upon superimposing the Aib horizon on the well-known iridium and fern-spore spikes, as its stratigraphic position precisely matches that predicted by the fungal spike. If correct, this hypothesis alters the conventional perspective on the tempo and mode of terrestrial ecosystem recovery in western North America, as the heavily sampled K/Pg boundary section in the Raton Basin was instrumental in shaping the traditional narrative of the rapid recolonization of a denuded landscape by ferns via wind-blown spores in the immediate wake of regional deforestation caused by the K/Pg impact event. Perhaps more importantly, it could present an alternative to traditional palynological approaches for locating the fungal spike in other terrestrial K/Pg boundary sections and could provide additional support for the generalization that global mass-extinction events are frequently accompanied by fungal spikes.

Deposition and age of Chicxulub impact spherules on Gorgonilla Island, Colombia

2019 ◽  
Vol 132 (1-2) ◽  
pp. 215-232
Author(s):  
Paula Mateo ◽  
Gerta Keller ◽  
Thierry Adatte ◽  
André M. Bitchong ◽  
Jorge E. Spangenberg ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Tectonic Activity ◽  
Sea Level Fluctuations ◽  
Variable Extent ◽  
Stratigraphic Position ◽  
Radiolarian Biostratigraphy ◽  
Absolute Age ◽  
Chicxulub Impact ◽  
The Impact ◽  
Primary Impact

AbstractThe end-Cretaceous mass extinction (66 Ma) has long been associated with the Chicxulub impact on the Yucatan Peninsula. However, consensus on the age of this impact has remained controversial because of differing interpretations on the stratigraphic position of Chicxulub impact spherules relative to the mass extinction horizon. One side argues that the impact occurred precisely at the Cretaceous-Paleogene boundary, thus coinciding with the mass extinction; the other side argues that the impact predated the Cretaceous-Paleogene boundary, based on the discovery of primary impact spherules deposits in NE Mexico and Texas near the base of planktic foraminiferal zone CF1, dated at 170 k.y. before the Cretaceous-Paleogene boundary. A recent study of the most pristine Chicxulub impact spherules discovered on Gorgonilla Island, Colombia, suggested that they represent a primary impact deposit with an absolute age indistinguishable from the Cretaceous-Paleogene boundary. Here, we report on the Gorgonilla section with the main objective of evaluating the nature of deposition and age of the spherule-rich layer relative to the Cretaceous-Paleogene boundary.The Gorgonilla section consists of light gray-yellow calcareous siliceous mudstones (pelagic deposits) alternating with dark olive-brown litharenites (turbidites). A 3-cm-thick dark olive-green spherule-rich layer overlies an erosional surface separating Maastrichtian and Danian sediments. This layer consists of a clast-supported, normally graded litharenite, with abundant Chicxulub impact glass spherules, lithics (mostly volcanic), and Maastrichtian as well as Danian microfossils, which transitions to a calcareous mudstone as particle size decreases. Mineralogical analysis shows that this layer is dominated by phyllosilicates, similar to the litharenites (turbidites) that characterize the section. Based on these results, the spherule-rich layer is interpreted as a reworked early Danian deposit associated with turbiditic currents. A major hiatus (>250 k.y.) spanning the Cretaceous-Paleogene boundary and the earliest Danian is recorded at the base of the spherule-rich layer, based on planktic foraminiferal and radiolarian biostratigraphy and carbon stable isotopes. Erosion across the Cretaceous-Paleogene boundary has been recorded worldwide and is generally attributed to rapid climate changes, enhanced bottom-water circulation during global cooling, sea-level fluctuations, and/or intensified tectonic activity. Chicxulub impact spherules are commonly reworked and redeposited into younger sediments overlying a Cretaceous-Paleogene boundary hiatus of variable extent in the Caribbean, Central America, and North Atlantic, while primary deposits are rare and only known from NE Mexico and Texas. Because of their reworked nature, Gorgonilla spherules provide no stratigraphic evidence from which the timing of the impact can be inferred.

scholarly journals A Hiatus Obscures the Early Evolution of Modern Lineages of Bony Fishes

2021 ◽  
Vol 8 ◽  
Author(s):  
Carlo Romano
Keyword(s):  
Mass Extinction ◽  
Fossil Record ◽  
Middle Triassic ◽  
Early Evolution ◽  
Early Triassic ◽  
Triassic Boundary ◽  
Bony Fishes ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
The Impact

About half of all vertebrate species today are ray-finned fishes (Actinopterygii), and nearly all of them belong to the Neopterygii (modern ray-fins). The oldest unequivocal neopterygian fossils are known from the Early Triassic. They appear during a time when global fish faunas consisted of mostly cosmopolitan taxa, and contemporary bony fishes belonged mainly to non-neopterygian (“paleopterygian”) lineages. In the Middle Triassic (Pelsonian substage and later), less than 10 myrs (million years) after the Permian-Triassic boundary mass extinction event (PTBME), neopterygians were already species-rich and trophically diverse, and bony fish faunas were more regionally differentiated compared to the Early Triassic. Still little is known about the early evolution of neopterygians leading up to this first diversity peak. A major factor limiting our understanding of this “Triassic revolution” is an interval marked by a very poor fossil record, overlapping with the Spathian (late Olenekian, Early Triassic), Aegean (Early Anisian, Middle Triassic), and Bithynian (early Middle Anisian) substages. Here, I review the fossil record of Early and Middle Triassic marine bony fishes (Actinistia and Actinopterygii) at the substage-level in order to evaluate the impact of this hiatus–named herein the Spathian–Bithynian gap (SBG)–on our understanding of their diversification after the largest mass extinction event of the past. I propose three hypotheses: 1) the SSBE hypothesis, suggesting that most of the Middle Triassic diversity appeared in the aftermath of the Smithian-Spathian boundary extinction (SSBE; ∼2 myrs after the PTBME), 2) the Pelsonian explosion hypothesis, which states that most of the Middle Triassic ichthyodiversity is the result of a radiation event in the Pelsonian, and 3) the gradual replacement hypothesis, i.e. that the faunal turnover during the SBG was steady and bony fishes were not affected by extinction events subsequent to the PTBME. Based on current knowledge, hypothesis three is favored herein, but further studies are necessary to test alternative hypotheses. In light of the SBG, claims of a protracted diversification of bony fishes after the PTBME should be treated with caution.

scholarly journals Morphological selectivity of the Permian-Triassic ammonoid mass extinction

Geology ◽  
2021 ◽  
Author(s):  
Xu Dai ◽  
Dieter Korn ◽  
Haijun Song
Keyword(s):  
Multidimensional Scaling ◽  
Mass Extinction ◽  
Nonmetric Multidimensional Scaling ◽  
Morphological Data ◽  
Early Triassic ◽  
Late Permian ◽  
Scaling Method ◽  
Data Set ◽  
Rapid Diversification ◽  
The Impact

Ammonoids suffered a diversity bottleneck during the Permian-Triassic mass extinction (PTME) and experienced a rapid diversification in the Early Triassic. However, the kinds of ammonoids that were more likely to survive the PTME and that fueled subsequent diversification are still poorly known. We compiled a comprehensive morphological data set and used the nonmetric multidimensional scaling method to reveal the impact of the PTME on the morphological selectivity of ammonoids. Our results show that postextinction taxa occupied a quite different morphospace when compared with the pre-extinction assemblages. The survivors were mainly smooth and weakly ornamented forms, while the late Permian species were dominated by coarsely ornamented forms. Contrary to previously recognized nonselective patterns, these results suggest a morphological selectivity of the Permian-Triassic crisis. Newcomers in the Griesbachian were mainly compressed and smooth forms. This morphological shift from the coarsely ornamented ammonoids dominating the Changhsingian to the smooth ammonoids dominating the Griesbachian possibly suggests an ecological turnover of ammonoids during the PTME.

Theories of Terrestrial Mass Extinction by Extraterrestrial Objects

1998 ◽  
Vol 17 (2) ◽  
pp. 157-173 ◽  
Author(s):  
Steven D'Hondt
Keyword(s):  
Twentieth Century ◽  
Mass Extinction ◽  
Mass Extinctions ◽  
Proximate Cause ◽  
Late Twentieth ◽  
Proximate Causes ◽  
Biological Extinction ◽  
Luis Alvarez ◽  
The Impact ◽  
Late Twentieth Century

Theories of mass extinction by extraterrestrial objects have been intermittently proposed by European and North American scientists for at least 250 years. Until the late twentieth century, such theories usually treated biological extinction as a single aspect of global cataclysm. Proposed ultimate causes of mass extinction have included the passage of planetesimals close to Earth, impacts of comets or asteroids, and transient increases in cosmic radiation. These theories have consistently extrapolated from astronomical observations to suggest that extraterrestrial objects had affected Earth at some time in the past. However, until the late twentieth century, none of these theories proposed definitive tests of temporal coincidences between mass extinctions and and the terrestrial effects of extraterrestrial objects. Harold Urey's (1973) cometary impact hypothesis was the first to propose such a test. The impact-extinction theory of Luis Alvarez and his colleagues (1980) was the first to provide direct evidence of such a coincidence. Such tests were probably not possible before the middle of the twentieth century. The failure of earlier theories to generate sustained scientific interest can be most simply attributed to their lack of such evidence. Theories of extraterrestrially caused mass extinction have almost always combined hypotheses of ultimate and proximate causes of extinction. The stability of these combinations has varied greatly from category to category and age to age. In general, these combinations evolved much more rapidly when they were presented and discussed in mainstream scientific literature. Despite their ubiquity, hypotheses of proximate causes have served a limited role in the reception of these theories. Scientific critics of these theories have consistently required hypotheses of proximate causes to appear plausible. However, the recent history of impact theories indicates that an ultimate cause of mass extinction may be widely accepted without definitive proof of the proximate cause of extinction.

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