Terminal Cretaceous catastrophe

McLean, Dewey M.

doi:10.1038/287760a0

Cited by 5 publications

(4 citation statements)

References 4 publications

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“…The view has been expressed that we will never know what happened at the C-T boundary, because a marine, regression at about that time destroyed the stratigraphic record, so that the boundary is always represented by a hiatus (e.g., McLean, 1980). This view is incorrect:…”

Section: Ultra-high-resolution Stratigraphymentioning

confidence: 90%

Current status of the impact theory for the terminal Cretaceous extinction

Álvarez¹,

Alvarez²,

Asaro³

et al. 1982

Geological Society of America Special Papers

112

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Section: Ultra-high-resolution Stratigraphymentioning

confidence: 90%

Current status of the impact theory for the terminal Cretaceous extinction

Álvarez¹,

Alvarez²,

Asaro³

et al. 1982

Geological Society of America Special Papers

112

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“…We also see some evidence for the 313C shift occurring somewhat earlier than the K/T boundary. Williams et al [1983] suggested that the 313C shift occurred earlier at site 516 ( Decreasing pH of the oceans as a result of proposed acid rains following a meteor impact [Lewis et al, 1982] or volcanism [McLean, 1980[McLean, ,1982 volume of shelf waters) in low-to mid-latitude regions where evaporation exceeds precipitation and inflow. They further argue that a large volume of the deep water masses in the Cretaceous oceans could have been composed of WSBW.…”

Section: Compatibility Of Interpretation and Models For The K/t Boundmentioning

confidence: 99%

Paleoceanography of the Cretaceous/Tertiary Boundary Event: Inferences from stable isotopic and other data

Zachos¹,

1986

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We report the results of new stable oxygen and carbon isotope analyses on carbonate fine fraction, whole rock, and benthic foraminifers, CaCO 3 and coarse fraction percentage determinations, and trace element (Sr) analyses on carbonate constitutents across the Cretaceous/Tertiary (K/T) boundary in Deep Sea Drilling Project (DSDP) sites 47.2, 356, 384, and 577 and compare them with published results from K/T boundary sections in other DSDP sites. We used the trace element data and scanning electron microscope examination to evaluate possible diagenetic alteration and relative preservation of the samples analyzed in this study. The 3180 data when interpreted as isotopic paleotemperatures indicate relative stable surface water and deepwater temperatures in the late Maestfichtian followed by somewhat fluctuating temperatures in the early Paleocene. However, there is no indication of either a significant warming or cooling at or following the K/T boundary. Several si: es do exhibit somewhat heavier 3180 values by about 0.5 %o across the boundary, which might suggest a 2-3øC cooling at most. However, we interpret these somewhat heavier 3180 values as reflecting slightly better preservation of 3180 of carbonate constitutents in relatively clay-rich intervals (e.g., lower diagentic potential) characteristic of the K/T boundary. The 313C values of carbonate fine fraction and planktonic foraminifers indicate a major negative excursion in surface water total dissolved carbon across the boundary. The surface water and deepwater 313C values from benthic foraminifers combined with calculated decreases in carbonate accumulation rates at all sites in the earliest Paleocene are consistent with a major decrease in productivity across the K/T boundary. The decrease in CaCO 3 accumulation rates is Copyright 1986 by the American Geophysical Union. Paper number 5PO837. 088 3-8305/8 6/005P-0 837510.00 due not to increased rates of dissolution but to decreased production in surface waters. The low-productivity episode lasted at least 1 m.y. beyond the K/T boundary crisis, suggesting that hypothesized catastrophic events alone, such as impact of an apollo object, are not the only explanation for the observed long-term decrease in productivity. There is also an indication in the 313C curves from several sites that the surface water 313C decrease began in the latest Maestfichtian, suggesting that the decrease in productivity may have been in&pendent of a hypothesized impact event.

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“…Recognition of the brevity of main eruptive activity on such large spatial scales has led to increasing recognition of flood basalt events as posing potentially catastrophic perturbations on Earth's surficial environs-the atmosphere, hydrosphere, and cryosphere and, consequently, the biosphere. Hypotheses linking flood basalt events to environmental crises have existed for decades and famously include the proposal by McLean (1980) that the Deccan Traps of modern India were the cause of the iconic mass extinction at the Cretaceous-Paleogene boundary. [We note that many flood basalt provinces are termed traps after the Swedish word trappa (stairs) in reference to the typical stairstep morphology of flood basalt outcrops.]…”

Section: Introductionmentioning

confidence: 99%

Flood Basalts and Mass Extinctions

Clapham

Renne

2019

Annu. Rev. Earth Planet. Sci.

114

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Flood basalts were Earth's largest volcanic episodes that, along with related intrusions, were often emplaced rapidly and coincided with environmental disruption: oceanic anoxic events, hyperthermals, and mass extinction events. Volatile emissions, both from magmatic degassing and vaporized from surrounding rock, triggered short-term cooling and longer-term warming, ocean acidification, and deoxygenation. The magnitude of biological extinction varied considerably, from small events affecting only select groups to the largest extinction of the Phanerozoic, with less-active organisms and those with less-developed respiratory physiology faring especially poorly. The disparate environmental and biological outcomes of different flood basalt events may at first order be explained by variations in the rate of volatile release modulated by longer trends in ocean carbon cycle buffering and the composition of marine ecosystems. Assessing volatile release, environmental change, and biological extinction at finer temporal resolution should be a top priority to refine ancient hyperthermals as analogs for anthropogenic climate change. ▪ Flood basalts, the largest volcanic events in Earth history, triggered dramatic environmental changes on land and in the oceans. ▪ Rapid volcanic carbon emissions led to ocean warming, acidification, and deoxygenation that often caused widespread animal extinctions. ▪ Animal physiology played a key role in survival during flood basalt extinctions, with reef builders such as corals being especially vulnerable. ▪ The rate and duration of volcanic carbon emission controlled the type of environmental disruption and the severity of biological extinction.

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Terminal Cretaceous catastrophe

Cited by 5 publications

References 4 publications

Current status of the impact theory for the terminal Cretaceous extinction

Current status of the impact theory for the terminal Cretaceous extinction

Paleoceanography of the Cretaceous/Tertiary Boundary Event: Inferences from stable isotopic and other data

Flood Basalts and Mass Extinctions

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