A Terminal Mesozoic "Greenhouse": Lessons from the Past

McLean, Dewey M.

doi:10.1126/science.201.4354.401

Cited by 73 publications

(19 citation statements)

References 22 publications

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“…Many of the widely cited hiatuses obliterating the carbonate record across the boundary are of very long duration and are caused by erosional events in the Cenozoic. These observations clearly contradict the popular model of a causal dependency of CO2 increase precipitating calcareous phytoplankton extinctions (Tappan, 1968;Worsley, 1974;McLean, 1978;Hsu, 1980).…”

Section: Calcareous Nannofossilsmentioning

confidence: 60%

Terminal Cretaceous plankton extinctions: A critical assessment

Thierstein

1982

Geological Society of America Special Papers

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All known groups of fossilized siliceous and calcareous phyto-and zooplankton experienced major, sudden extinctions of unique severity at the very end of the Cretaceous. Evolutionary diversification of the earliest Tertiary nannofossil assemblages was rapid and highly variable in space and through time. Biogeographic and stratigraphic studies of calcareous nannofossils suggest stable ecologic conditions in oceanic environments during the last several million years of Cretaceous time. Wellpreserved earliest Danian calcareous nannoplankton assemblages from several apparently continuous deep sea sequences dispel the notion of a major global dissolution event related to the mass extinctions. Available paleontological evidence indicates that the extinctions were highly selective and affected the following paleoenvironments with decreasing severity: open ocean surface waters, shallow coastal waters, terrestrial environments, fresh water habitats, deep ocean waters. A total blackout of a few weeks' to months' duration appears consistent with the fossil evidence and with light requirements of living phytoplankton. However, stratigraphic resolution in boundary sections is insufficient, and present ignorance of the geochemistry of noble elements too extensive, to exclude terrestrial metal enrichment processes unrelated to an extraterrestrial impact. THE CASE FOR A CATASTROPHEConvincing evidence for a major and sudden mass extinction of the oceanic calcareous plankton (coccolithosphores and foraminifera) at the end of the Mesozoic Era has been accumulating over the past few years (Bramlette and Martini, 1964;Luterbacher and Premoli Silva, 1964;Kent, 1977;Thierstein, 1981). Far less, however, is known of the evolutionary turnover of other plankton groups, of the marine benthos,-and of terrestrial organisms. This is mostly due to the scarcity of stratigraphic sections available for study, the small sample sizes of preserved fossils, and the limited stratigraphic resolution in most available sections. It is generally data from these less well known fossil groups that have led to non-catastrophic interpretations of the Cretaceous-Tertiary boundary events (Kauffman, 1979;Clemens and Archibald, 1980;Hickey, 1981).Sources of biotic stress that may have resulted in mass extinctions have been reviewed by Russell (1979). Since then two additional models derived from evidence in pelagic marine sections have been widely discussed in the literature. The first one postulated salinity changes of oceanic surface waters caused by reconnection of a temporarily isolated Arctic Ocean (Gartner and Keany, 1978;Thierstein and Berger, 1978;Gartner and McGuirk, 1979). The second model is based on the anomalous chemistry of boundary clays (Alvarez et al" 1980;Ganapathy, 1980;Smit and Hertogen, 1980) and revitalized earlier proposals of extraterrestrial large body impacts (De Laubenfels, 1956; Urey, 1973;Lemcke, 1975).In the following review I will first examine the extinction patterns in various plankton groups, including the non-calcareous ones, a...

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Section: Calcareous Nannofossilsmentioning

confidence: 60%

Terminal Cretaceous plankton extinctions: A critical assessment

Thierstein

1982

Geological Society of America Special Papers

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“…The most massive eruptions reached over 1000 km across India and out to the Gulf of Bengal, forming the longest lava fl ows known on Earth (Self et al 2008a). It is therefore no surprise that scientists advocated Deccan volcanism as the major contributor or cause of the KT mass extinction even before the impact theory was proposed (McLean 1978) and through the 1980-1990s (McLean 1985Courtillot et al 1986Courtillot et al , 1988Courtillot 1999). Over the past decade continental fl ood basalts (CFB) have been correlated with most major mass extinctions (Wignall 2001) leading Courtillot and Renne (2003) to suggest that this may be the general cause of mass extinctions.…”

Section: Introductionmentioning

confidence: 98%

Deccan volcanism, the KT mass extinction and dinosaurs

2009

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Recent advances in Deccan volcanic studies indicate three volcanic phases with the phase-1 at 67.5 Ma followed by a 2 m.y. period of quiescence. Phase-2 marks the main Deccan volcanic eruptions in Chron 29r near the end of the Maastrichtian and accounts for approximately 80% of the entire 3500 m thick Deccan lava pile. At least four of the world's longest lava flows spanning 1000 km across India and out into the Gulf of Bengal mark phase-2. The final phase-3 was smaller, coincided with the early Danian Chron 29n and also witnessed several of the longest lava flows. The KT boundary and mass extinction was first discovered based on planktic foraminifera from shallow marine intertrappean sediments exposed in Rajahmundry quarries between the longest lava flows of the main volcanic phase-2 and smaller phase-3. At this locality early Danian (zone P1a) planktic foraminiferal assemblages directly overlie the top of phase-2 eruptions and indicate that the masse extinction coincided with the end of this volcanic phase. Planktic foraminiferal assemblages also mark the KT boundary in intertrappean sediments at Jhilmili, Chhindwara, where freshwater to estuarine conditions prevailed during the early Danian and indicate the presence of a marine seaway across India at KT time. Dinosaur bones, nesting sites with complete eggs and abundant eggshells are known from central India surrounding the hypothesized seaway through the Narmada-Tapti rift zone. A Maastrichtian age is generally assigned to these dinosaur remains. Age control may now be improved based on marine microfossils from sequences deposited in the seaway and correlating these strata to nearby terrestrial sequences with dinosaur remains.

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“…However, volcanic exhalations from the mantle can be also iridium-enriched as observed in volcanic systems such as Piton de La Fournaise, Indic ocean (Toutain and Meyer, 1989) and in Kilauea, Hawai (Zoller et al, 1983). The largest volcanic eruptions in the Late Maastrichtian and Early Danian in Deccan in India could support a hypothesis that volcanism may have played important role in a dramatic change of climatic conditions during the CretaceousePaleogene transition (McLean, 1978(McLean, , 1991Chatterjee et al, 2003). As already known, the largest Permian-Triassic transition mass extinction coincides with basaltic floods in Siberia (Campbell et al, 1992;Renne et al, 1995;Berner, 2002;Beerling et al, 2007).…”

Section: Introductionmentioning

confidence: 92%