scholarly journals USING MOLYBDENUM ISOTOPES TO RECONSTRUCT MARINE REDOX CHANGE THROUGH THE END TRIASSIC MASS EXTINCTION EVENT

2021 ◽  
Author(s):  
Andrew Bond ◽  
Alex Dickson ◽  
Micha Ruhl
Keyword(s):  
Mass Extinction ◽  
Molybdenum Isotopes ◽  
Extinction Event ◽  
Redox Change ◽  
Mass Extinction Event

THE RECORD OF ENVIRONMENTAL CHANGE IN NORTHEASTERN PANTHALASSA DIRECTLY PRECEDING THE END-TRIASSIC MASS EXTINCTION EVENT

2019 ◽  
Author(s):  
Ekaterina Larina ◽  
◽  
David J. Bottjer ◽  
Frank A. Corsetti ◽  
William M. Berelson ◽  
...  
Keyword(s):  
Environmental Change ◽  
Mass Extinction ◽  
Extinction Event ◽  
Mass Extinction Event

SEDIMENTARY MERCURY CONCENTRATIONS AND ISOTOPES ACROSS THE END-CRETACEOUS MASS EXTINCTION EVENT FROM NEW JERSEY

2020 ◽  
Author(s):  
Marisa D. Knight ◽  
◽  
Runsheng Yin ◽  
Clara L. Meier ◽  
James V. Browning ◽  
...  
Keyword(s):  
New Jersey ◽  
Mass Extinction ◽  
Extinction Event ◽  
Mass Extinction Event

scholarly journals Dinosaurs in decline tens of millions of years before their final extinction

2016 ◽  
Vol 113 (18) ◽  
pp. 5036-5040 ◽  
Author(s):  
Manabu Sakamoto ◽  
Michael J. Benton ◽  
Chris Venditti
Keyword(s):  
Mass Extinction ◽  
Marked Reduction ◽  
Evolutionary Dynamics ◽  
General Pattern ◽  
Extinction Rate ◽  
Catastrophic Event ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
First Time

Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous–Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

scholarly journals New Biochronological Scales of Planktic Foraminifera for the Early Danian Based on High-Resolution Biostratigraphy

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 479
Author(s):  
Ignacio Arenillas ◽  
Vicente Gilabert ◽  
José A. Arz
Keyword(s):  
High Resolution ◽  
Mass Extinction ◽  
Quantitative Data ◽  
Qualitative Data ◽  
Rapid Evolution ◽  
Planktic Foraminifera ◽  
Middle Latitudes ◽  
Evolutionary Radiation ◽  
Extinction Event ◽  
Mass Extinction Event

After the Cretaceous/Paleogene boundary (KPB) catastrophic mass extinction event, an explosive evolutionary radiation of planktic foraminifera took place in consequence of the prompt occupation of empty niches. The rapid evolution of new species makes it possible to establish high-resolution biozonations in the lower Danian. We propose two biostratigraphic scales for low-to-middle latitudes spanning the first two million years of the Danian. The first is based on qualitative data and includes four biozones: the Guembelitria cretacea Zone (Dan1), the Parvularugoglobigerina longiapertura Zone (Dan2), the Parvularugoglobigerina eugubina Zone (Dan3), and the Parasubbotina pseudobulloides Zone (Dan4). The latter two are divided into several sub-biozones: the Parvularugoglobigerina sabina Subzone (Dan3a) and the Eoglobigerina simplicissima Subzone (Dan3b) for the Pv. eugubina Zone, and the Praemurica taurica Subzone (Dan4a), the Subbotina triloculinoides Subzone (Dan4b), and the Globanomalina compressa Subzone (Dan4c) for the P. pseudobulloides Zone. The second scale is based on quantitative data and includes three acme-zones (abundance zones): the Guembelitria Acme-zone (DanAZ1), the Parvularugoglobigerina-Palaeoglobigerina Acme-zone (DanAZ2), and the Woodringina-Chiloguembelina Acme-zone (DanAZ3). Both biozonations are based on high-resolution samplings of the most continuous sections of the lower Danian worldwide and have been calibrated with recent magnetochronological and astrochronological dating.

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
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