A NEW PANTHALASSAN IRON-OOLITE DEPOSIT FROM THE EARLY JURASSIC: IMPLICATIONS FOR GLOBAL SHALLOW MARINE IRON DEPOSITION IN THE AFTERMATH OF THE END-TRIASSIC MASS EXTINCTION

2018 ◽  
Author(s):  
Annaka M. Clement ◽  
◽  
Lydia S. Tackett ◽  
Kathleen A. Ritterbush ◽  
Yadira Ibarra
Keyword(s):  
Mass Extinction ◽  
Early Jurassic ◽  
Iron Deposition ◽  
Shallow Marine

scholarly journals A review of Palaeozoic and Mesozoic tetrapods from Greenland

2018 ◽  
Vol 66 ◽  
pp. 21-46 ◽  
Author(s):  
Marco Marzola ◽  
Octávio Mateus ◽  
Jesper Milàn ◽  
Lars B. Clemmensen
Keyword(s):  
Late Jurassic ◽  
Early Jurassic ◽  
Late Carboniferous ◽  
Late Triassic ◽  
Late Devonian ◽  
Early Triassic ◽  
Shallow Marine ◽  
East Greenland ◽  
Marine Deposits ◽  
Theropod Dinosaurs

This article presents a synthesis of Palaeozoic and Mesozoic fossil tetrapods from Greenland, including an updated review of the holotypes and a new photographic record of the main specimens. All fossil tetrapods found are from East Greenland, with at least 30 different known taxa: five stem tetrapods (Acanthostega gunnari, Ichthyostega eigili, I. stensioi, I. watsoni, and Ymeria denticulata) from the Late Devonian of the Aina Dal and Britta Dal Formations; four temnospondyl amphibians (Aquiloniferus kochi, Selenocara groenlandica, Stoschiosaurus nielseni, and Tupilakosaurus heilmani) from the Early Triassic of the Wordie Creek Group; two temnospondyls (Cyclotosaurus naraserluki and Gerrothorax cf. pulcherrimus), one testudinatan (cf. Proganochelys), two stagonolepids (Aetosaurus ferratus and Paratypothorax andressorum), the eudimorphodontid Arcticodactylus, undetermined archosaurs (phytosaurs and both sauropodomorph and theropod dinosaurs), the cynodont Mitredon cromptoni, and three mammals (Haramiyavia clemmenseni, Kuehneotherium, and cf. ?Brachyzostrodon), from the Late Triassic of the Fleming Fjord Formation; one plesiosaur from the Early Jurassic of the Kap Stewart Formation; one plesiosaur and one ichthyosaur from the Late Jurassic of the Kap Leslie Formation, plus a previously unreported Late Jurassic plesiosaur from Kronprins Christian Land. Moreover, fossil tetrapod trackways are known from the Late Carboniferous (morphotype Limnopus) of the Mesters Vig Formation and at least four different morphologies (such as the crocodylomorph Brachychirotherium, the auropodomorph Eosauropus and Evazoum, and the theropodian Grallator) associated to archosaurian trackmakers are known from the Late Triassic of the Fleming Fjord Formation. The presence of rich fossiliferous tetrapod sites in East Greenland is linked to the presence of well-exposed continental and shallow marine deposits with most finds in terrestrial deposits from the Late Devonian and the Late Triassic.

scholarly journals Triassic–Jurassic mass extinction as trigger for the Mesozoic radiation of crocodylomorphs

2013 ◽  
Vol 9 (3) ◽  
pp. 20130095 ◽  
Author(s):  
Olja Toljagić ◽  
Richard J. Butler
Keyword(s):  
Mass Extinction ◽  
Evolutionary History ◽  
Morphological Diversity ◽  
Early Jurassic ◽  
Late Triassic ◽  
Time Interval ◽  
Significant Shift ◽  
History Of ◽  
Larger Sample ◽  
Lineage Diversity

Pseudosuchia, one of the two main clades of Archosauria (Reptilia: Diapsida), suffered a major decline in lineage diversity during the Triassic–Jurassic (TJ) mass extinction (approx. 201 Ma). Crocodylomorpha, including living crocodilians and their extinct relatives, is the only group of pseudosuchians that survived into the Jurassic. We reassess changes in pseudosuchian morphological diversity (disparity) across this time interval, using considerably larger sample sizes than in previous analyses. Our results show that metrics of pseudosuchian disparity did not change significantly across the TJ boundary, contrasting with previous work suggesting low pseudosuchian disparity in the Early Jurassic following the TJ mass extinction. However, a significant shift in morphospace occupation between Late Triassic and Early Jurassic taxa is recognized, suggesting that the TJ extinction of many pseudosuchian lineages was followed by a major and geologically rapid adaptive radiation of crocodylomorphs. This marks the onset of the spectacularly successful evolutionary history of crocodylomorphs in Jurassic and Cretaceous ecosystems.

scholarly journals Thallium isotopes reveal protracted anoxia during the Toarcian (Early Jurassic) associated with volcanism, carbon burial, and mass extinction

2018 ◽  
Vol 115 (26) ◽  
pp. 6596-6601 ◽  
Author(s):  
Theodore R. Them ◽  
Benjamin C. Gill ◽  
Andrew H. Caruthers ◽  
Angela M. Gerhardt ◽  
Darren R. Gröcke ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Biological Evolution ◽  
Oxygen Depletion ◽  
Early Jurassic ◽  
Large Igneous Province ◽  
Mass Extinctions ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Anoxic Basins ◽  
Bottom Waters

For this study, we generated thallium (Tl) isotope records from two anoxic basins to track the earliest changes in global bottom water oxygen contents over the Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma) of the Early Jurassic. The T-OAE, like other Mesozoic OAEs, has been interpreted as an expansion of marine oxygen depletion based on indirect methods such as organic-rich facies, carbon isotope excursions, and biological turnover. Our Tl isotope data, however, reveal explicit evidence for earlier global marine deoxygenation of ocean water, some 600 ka before the classically defined T-OAE. This antecedent deoxygenation occurs at the Pliensbachian/Toarcian boundary and is coeval with the onset of initial large igneous province (LIP) volcanism and the initiation of a marine mass extinction. Thallium isotopes are also perturbed during the T-OAE interval, as defined by carbon isotopes, reflecting a second deoxygenation event that coincides with the acme of elevated marine mass extinctions and the main phase of LIP volcanism. This suggests that the duration of widespread anoxic bottom waters was at least 1 million years in duration and spanned early to middle Toarcian time. Thus, the Tl data reveal a more nuanced record of marine oxygen depletion and its links to biological change during a period of climatic warming in Earth’s past and highlight the role of oxygen depletion on past biological evolution.

scholarly journals Modelling determinants of extinction across two Mesozoic hyperthermal events

2018 ◽  
Vol 285 (1889) ◽  
pp. 20180404 ◽  
Author(s):  
Alexander M. Dunhill ◽  
William J. Foster ◽  
Sandro Azaele ◽  
James Sciberras ◽  
Richard J. Twitchett
Keyword(s):  
Mass Extinction ◽  
Marine Organisms ◽  
Early Jurassic ◽  
Late Triassic ◽  
Global Database ◽  
Extinction Rates ◽  
Multivariate Modelling ◽  
Hyperthermal Events ◽  
Extinction Selectivity ◽  
Extinction Events

The Late Triassic and Early Toarcian extinction events are both associated with greenhouse warming events triggered by massive volcanism. These Mesozoic hyperthermals were responsible for the mass extinction of marine organisms and resulted in significant ecological upheaval. It has, however, been suggested that these events merely involved intensification of background extinction rates rather than significant shifts in the macroevolutionary regime and extinction selectivity. Here, we apply a multivariate modelling approach to a vast global database of marine organisms to test whether extinction selectivity varied through the Late Triassic and Early Jurassic. We show that these hyperthermals do represent shifts in the macroevolutionary regime and record different extinction selectivity compared to background intervals of the Late Triassic and Early Jurassic. The Late Triassic mass extinction represents a more profound change in selectivity than the Early Toarcian extinction but both events show a common pattern of selecting against pelagic predators and benthic photosymbiotic and suspension-feeding organisms, suggesting that these groups of organisms may be particularly vulnerable during episodes of global warming. In particular, the Late Triassic extinction represents a macroevolutionary regime change that is characterized by (i) the change in extinction selectivity between Triassic background intervals and the extinction event itself; and (ii) the differences in extinction selectivity between the Late Triassic and Early Jurassic as a whole.

4. The great catastrophes

2019 ◽  
pp. 51-75
Author(s):  
Paul B. Wignall
Keyword(s):  
Big Five ◽  
Mass Extinction ◽  
Early Jurassic ◽  
Late Devonian ◽  
Mass Extinctions ◽  
Short Intervals ◽  
Extinction Rates ◽  
The World ◽  
Extinction Events ◽  
Mass Extinction Events

What is a mass extinction? Mass extinction events are geologically short intervals of time (always under a million years), marked by dramatic increases of extinction rates in a broad range of environments around the world. In essence they are global catastrophes that left no environment unaffected and that have fundamentally changed the trajectory of life. ‘The great catastrophes’ describes the big five mass extinctions—the end-Ordovician 445 million years ago, the Late Devonian 374 million years ago, the Permo-Triassic 252 million years ago, the end-Triassic 201 million years ago, and Cretaceous-Paleogene sixty-six million years ago—and thoughts on their likely causes, along with other important extinction events identified at the start of the Cambrian and in the Early Jurassic.

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