Cretaceous Extinctions: Evidence Overlooked

Keller, Gerta; Adatte, Thierry; Pardo, Alfonso; Bajpai, Sunil; Khosla, Ashu; Samant, Bandana

doi:10.1126/science.328.5981.974-a

Cited by 54 publications

(33 citation statements)

References 9 publications

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“…Whether this event was caused by the devastating impact of an extra-terrestrial object (Alvarez et al, 40 1980; Schulte et al, 2010; Renne et al, 2013), or was drawn out through the final few million years of 41 the Cretaceous, with other factors such as climate and sea level changes or the environmental effects 42 of large scale flood basalt volcanism playing a primary role (Archibald et al, 2010; Courtillot and 43 Fluteau, 2010;Keller et al, 2010). 44…”

Section: Introduction 36mentioning

confidence: 99%

Evolution and extinction of Maastrichtian (Late Cretaceous) cephalopods from the López de Bertodano Formation, Seymour Island, Antarctica

Witts

Bowman

Wignall

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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8One of the most expanded records to contain the final fortunes of ammonoid cephalopods is within 9 the López de Bertodano Formation of Seymour Island, James Ross Basin, Antarctica. Located at~65º 10 South now, and during the Cretaceous, this sequence is the highest southern latitude onshore outcrop 11 containing the Cretaceous-Paleogene (K-Pg) transition. We present comprehensive new 12 biostratigraphic range data for 14 ammonite and one nautiloid species based on the collection of >700 13 macrofossils from high-resolution sampling of parallel sedimentary sections, dated Maastrichtian to 14 earliest Danian in age, across southern Seymour Island. We find evidence for only a single, abrupt 15 pulse of cephalopod extinction at the end of the Cretaceous when the final seven ammonite species 16 disappeared, consistent with most evidence globally. In the lead up to the K-Pg extinction in the 17 James Ross Basin, starting during the Campanian, ammonite diversity decreased overall, but the 18 number of endemic taxa belonging to the family Kossmaticeratidae actually increased. This pattern 19 continued into the Maastrichtian and may be facies controlled, linked to changes in sea level and 20 seawater temperature. During the early Maastrichtian, ammonite diversity dropped significantly with 21 only two species recorded from the basal López de Bertodano Formation on Seymour Island. The 22 subsequent diversification of endemic taxa and reappearance of long-ranging, widespread species into 23 the basin resulted in an increase in ammonite diversity and abundance during the mid- Maastrichtian. 24 This was coincident with an apparent period of warming temperatures and sea level rise interpreted 25 from palynology and sedimentology, perhaps reflecting a high latitude expression of the Maastrichtian Event. Late Maastrichtian diversity levels remained stable despite reported climatic and 27 environmental variation. Ammonite diversity patterns during the Maastrichtian parallel those of 28 microfossil species such as nannofossil and planktonic foraminifera, suggesting that dynamic climatic 29 and environmental changes affected many planktonic and nektonic organisms during the latest 30Cretaceous. However, we suggest that these perturbations had a minimal effect on overall diversity 31 prior to the catastrophic extinction event at the K-Pg boundary. 32 33 3 Key words: Cretaceous; palaeoenvironments; ammonite; extinction; Antarctica; diversity. 34 35 1.Introduction 36The final demise of the ammonoid cephalopods at the end of the Cretaceous is a key 37 component of the ongoing debate about the nature of the Cretaceous -Paleogene (K-Pg) boundary 38 mass extinction event of 66 Ma (Gallagher, 1991;Ward et al., 1991;Marshall and Ward, 1996). 39Whether this event was caused by the devastating impact of an extra-terrestrial object (Alvarez et al., 40 1980; Schulte et al., 2010; Renne et al., 2013), or was drawn out through the final few million years of 41 the Cretaceous, with other factors such as climate and sea level cha...

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Section: Introduction 36mentioning

confidence: 99%

Evolution and extinction of Maastrichtian (Late Cretaceous) cephalopods from the López de Bertodano Formation, Seymour Island, Antarctica

Witts

Bowman

Wignall

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

View full text Add to dashboard Cite

show abstract

“…However, seemingly diagnostic evidence of impact is strongly contested (e.g. Keller and Stinnesbeck, 1996) and patterns of biological turnover fail to correlate clearly with a single causal mechanism (Keller et al, 2010), leading several workers to favour other less catastrophic processes, such as prolonged volcanic activity from the Deccan Traps (e.g. Valen, 1984;Officer and Drake, 1985;, as explanations for the K-T mass extinction.…”

Section: Introductionmentioning

confidence: 99%

Environmental change prior to the K–T boundary inferred from temporal variation in the morphology of cheilostome bryozoans

O’Dea

Håkansson

Taylor

et al. 2011

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…Hallam and Wignall, 1997). In particular, the debate over the importance of a single large asteroid impact on the Yucatán Peninsula synchronously with the K-Pg boundary remains controversial (Archibald et al, 2010;Courtillot and Fluteau, 2010;Keller et al, 2010;Schulte et al, 2010a,b).…”

Section: Geochronology Of Impacts Flood Basalts and Mass Extinctionsmentioning

confidence: 99%

The Geochronology of Impact Craters

Kelley

Sherlock

2012

Impact Cratering

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Cretaceous Extinctions: Evidence Overlooked

Cited by 54 publications

References 9 publications

Evolution and extinction of Maastrichtian (Late Cretaceous) cephalopods from the López de Bertodano Formation, Seymour Island, Antarctica

Evolution and extinction of Maastrichtian (Late Cretaceous) cephalopods from the López de Bertodano Formation, Seymour Island, Antarctica

Environmental change prior to the K–T boundary inferred from temporal variation in the morphology of cheilostome bryozoans

The Geochronology of Impact Craters

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