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Continental flood basalts drive Phanerozoic extinctions. Proc Natl Acad Sci U S A 2022; 119:e2120441119. [PMID: 36095185 PMCID: PMC9499591 DOI: 10.1073/pnas.2120441119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Refinements of the geological timescale driven by the increasing precision and accuracy of radiometric dating have revealed an apparent correlation between large igneous provinces (LIPs) and intervals of Phanerozoic faunal turnover that has been much discussed at a qualitative level. However, the extent to which such correlations are likely to occur by chance has yet to be quantitatively tested, and other kill mechanisms have been suggested for many mass extinctions. Here, we show that the degree of temporal correlation between continental LIPs and faunal turnover in the Phanerozoic is unlikely to occur by chance, suggesting a causal relationship linking extinctions and continental flood basalts. The relationship is stronger for LIPs with higher estimated eruptive rates and for stage boundaries with higher extinction magnitudes. This suggests LIP magma degassing as a primary kill mechanism for mass extinctions and other intervals of faunal turnover, which may be related to [Formula: see text], Cl, and F release. Our results suggest continental LIPs as a major, direct driver of extinctions throughout the Phanerozoic.
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Snyder-Beattie AE, Ord T, Bonsall MB. An upper bound for the background rate of human extinction. Sci Rep 2019; 9:11054. [PMID: 31363134 PMCID: PMC6667434 DOI: 10.1038/s41598-019-47540-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/19/2019] [Indexed: 01/11/2023] Open
Abstract
We evaluate the total probability of human extinction from naturally occurring processes. Such processes include risks that are well characterized such as asteroid impacts and supervolcanic eruptions, as well as risks that remain unknown. Using only the information that Homo sapiens has existed at least 200,000 years, we conclude that the probability that humanity goes extinct from natural causes in any given year is almost guaranteed to be less than one in 14,000, and likely to be less than one in 87,000. Using the longer track record of survival for our entire genus Homo produces even tighter bounds, with an annual probability of natural extinction likely below one in 870,000. These bounds are unlikely to be affected by possible survivorship bias in the data, and are consistent with mammalian extinction rates, typical hominin species lifespans, the frequency of well-characterized risks, and the frequency of mass extinctions. No similar guarantee can be made for risks that our ancestors did not face, such as anthropogenic climate change or nuclear/biological warfare.
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Affiliation(s)
- Andrew E Snyder-Beattie
- University of Oxford, Mathematical Ecology Research Group, Department of Zoology, Oxford, OX1 3SZ, UK.
| | - Toby Ord
- University of Oxford, Future of Humanity Institute, Faculty of Philosophy, Oxford, OX1 1PT, UK
| | - Michael B Bonsall
- University of Oxford, Mathematical Ecology Research Group, Department of Zoology, Oxford, OX1 3SZ, UK
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Benton MJ. Hyperthermal-driven mass extinctions: killing models during the Permian-Triassic mass extinction. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:20170076. [PMID: 30177561 PMCID: PMC6127390 DOI: 10.1098/rsta.2017.0076] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/23/2018] [Indexed: 05/06/2023]
Abstract
Many mass extinctions of life in the sea and on land have been attributed to geologically rapid heating, and in the case of the Permian-Triassic and others, driven by large igneous province volcanism. The Siberian Traps eruptions raised ambient temperatures to 35-40°C. A key question is how massive eruptions during these events, and others, could have killed life in the sea and on land; proposed killers are reviewed here. In the oceans, benthos and plankton were killed by anoxia-euxinia and lethal heating, respectively, and the habitable depth zone was massively reduced. On land, the combination of extreme heating and drought reduced the habitable land area, and acid rain stripped forests and soils. Physiological experiments show that some animals can adapt to temperature rises of a few degrees, and that some can survive short episodes of increases of 10°C. However, most plants and animals suffer major physiological damage at temperatures of 35-40°C. Studies of the effects of extreme physical conditions on modern organisms, as well as assumptions about rates of environmental change, give direct evidence of likely killing effects deriving from hyperthermals of the past.This article is part of a discussion meeting issue 'Hyperthermals: rapid and extreme global warming in our geological past'.
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Affiliation(s)
- Michael J Benton
- School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
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Self S, Thordarson T, Keszthelyi L. Emplacement of Continental Flood Basalt Lava Flows. LARGE IGNEOUS PROVINCES: CONTINENTAL, OCEANIC, AND PLANETARY FLOOD VOLCANISM 2013. [DOI: 10.1029/gm100p0381] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Eldholm O, Grue K. North Atlantic volcanic margins: Dimensions and production rates. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/93jb02879] [Citation(s) in RCA: 265] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Campbell IH, Czamanske GK, Fedorenko VA, Hill RI, Stepanov V. Synchronism of the siberian traps and the permian-triassic boundary. Science 2010; 258:1760-3. [PMID: 17831657 DOI: 10.1126/science.258.5089.1760] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Uranium-lead ages from an ion probe were taken for zircons from the ore-bearing Noril'sk I intrusion that is comagmatic with, and intrusive to, the Siberian Traps. These values match, within an experimental error of +/-4 million years, the dates for zircons extracted from a tuff at the Permian-Triassic (P-Tr) boundary. The results are consistent with the hypothesis that the P-Tr extinction was caused by the Siberian basaltic flood volcanism. It is likely that the eruption of these magmas was accompanied by the injection of large amounts of sulfur dioxide into the upper atmosphere, which may have led to global cooling and to expansion of the polar ice cap. The P-Tr extinction event may have been caused by a combination of acid rain and global cooling as well as rapid and extreme changes in sea level resulting from expansion of the polar ice cap.
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Courtillot V, Fluteau F. Cretaceous Extinctions: The Volcanic Hypothesis. Science 2010; 328:973-4; author reply 975-6. [DOI: 10.1126/science.328.5981.973-b] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Mass extinctions of life and catastrophic flood basalt volcanism. Proc Natl Acad Sci U S A 2010; 107:6555-6. [PMID: 20360556 DOI: 10.1073/pnas.1002478107] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Compound-specific carbon isotopes from Earth's largest flood basalt eruptions directly linked to the end-Triassic mass extinction. Proc Natl Acad Sci U S A 2010; 107:6721-5. [PMID: 20308590 DOI: 10.1073/pnas.1001706107] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A leading hypothesis explaining Phanerozoic mass extinctions and associated carbon isotopic anomalies is the emission of greenhouse, other gases, and aerosols caused by eruptions of continental flood basalt provinces. However, the necessary serial relationship between these eruptions, isotopic excursions, and extinctions has never been tested in geological sections preserving all three records. The end-Triassic extinction (ETE) at 201.4 Ma is among the largest of these extinctions and is tied to a large negative carbon isotope excursion, reflecting perturbations of the carbon cycle including a transient increase in CO(2). The cause of the ETE has been inferred to be the eruption of the giant Central Atlantic magmatic province (CAMP). Here, we show that carbon isotopes of leaf wax derived lipids (n-alkanes), wood, and total organic carbon from two orbitally paced lacustrine sections interbedded with the CAMP in eastern North America show similar excursions to those seen in the mostly marine St. Audrie's Bay section in England. Based on these results, the ETE began synchronously in marine and terrestrial environments slightly before the oldest basalts in eastern North America but simultaneous with the eruption of the oldest flows in Morocco, a CO(2) super greenhouse, and marine biocalcification crisis. Because the temporal relationship between CAMP eruptions, mass extinction, and the carbon isotopic excursions are shown in the same place, this is the strongest case for a volcanic cause of a mass extinction to date.
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Chenet AL, Fluteau F, Courtillot V, Gérard M, Subbarao KV. Determination of rapid Deccan eruptions across the Cretaceous-Tertiary boundary using paleomagnetic secular variation: Results from a 1200-m-thick section in the Mahabaleshwar escarpment. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2006jb004635] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Macleod N. Identifying Phanerozoic extinction controls: statistical considerations and preliminary results. ACTA ACUST UNITED AC 2004. [DOI: 10.1144/gsl.sp.2004.230.01.02] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractTwo prominent patterns have been recognized in Phanerozoic extinction data: (1) a quasi-periodic distribution of extinction-intensity peaks, and (2) a linear, declining background extinction intensity gradient. Characterization and interpretation of both patterns are necessary to understand Phanerozoic extinction controls. The extinction-intensity peak spectrum has been variously interpreted as a reflection of the time-series of major sea-level regressions, continental flood-basalt province (CFBP) eruptions, and bolide impacts. In order to evaluate the level of association between these time-series and the Phanerozoic marine invertebrate extinction record statistically, a new Monte Carlo simulation strategy is presented. Results of simulation-based tests suggest that the time-series of major, eustatic sea-level regressions and CFBP eruption events have a statistically significant (p ≤ 0.05) association with Tatarian-Pliocene, stage-level, extinction intensity peaks. Associations between this peak series and the time-series of crater-producing bolide impacts do not appear significant at this level. A limited multicausal event scenario was also tested using the Monte Carlo method, and recognized the combination of sea-level regression and CFBP volcanism to be significantly associated with the largest extinction intensity peaks of the last 250 Ma. The background extinction-intensity gradient has been interpreted variously as: (1) an indicator of progressive improvement in extinction resistance through selection; (2) the by-product of an invasion of marginal (extinction-resistant) habitats; and (3) as a taxonomic-stratigraphical artefact. Results of subdivided linear trend analyses suggest that the background extinction-intensity gradient is largely confined to the Late Palaeozoic-Cenozoic interval. No statistically significant gradient is present in the most recent compilation of Early-Middle Palaeozoic data on marine, invertebrate extinctions. The timing of gradient initiation and extinction variance analyses suggest that reorganization of global carbon cycles and oceanographical circulation patterns in the Devonian-Early Carboniferous, and the evolutionary appearance of modern phytoplankton groups in the Late Triassic both had dramatic effects on the character of the extinction-intensity gradient.
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Affiliation(s)
- N. Macleod
- Department of Palaeontology, The Natural History Museum
Cromwell Road, London, SW7 5BD, UK
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McHone JG. Volatile emissions from Central Atlantic Magmatic Province Basalts: Mass assumptions and environmental consequences. THE CENTRAL ATLANTIC MAGMATIC PROVINCE: INSIGHTS FROM FRAGMENTS OF PANGEA 2003. [DOI: 10.1029/136gm013] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Abstract
The recognition in 1980 of a signature of an extraterrestrial impact at the Cretaceous-Tertiary boundary and its apparent involvement with the mass extinction generated considerable enthusiasm for impacts at other mass extinctions. Numerous claims of impact evidence for the Permo-Triassic mass extinction (251.6 Ma), the largest of the Phanerozoic mass extinctions, have generally been rejected, found wanting, or been difficult to reproduce. Despite this lack of repeatable support, considerable available evidence is consistent with an impact, including the rapidity of extinction, coincident carbon shift, and evident correlation between terrestrial and marine extinctions. However attractive the hypothesis, the coincidence with the Siberian flood basalts and the complex nature of the carbon shift are in conflict with an impact. The most intriguing possibility is that the greatest mass extinction of the Phanerozoic left signals very similar to the end-Cretaceous mass extinction but was produced by entirely Earth-bound processes. If true, this would tell us far more about the nature of ecosystems and how they fail than would identification of another impact.
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Affiliation(s)
- Douglas H Erwin
- Department of Paleobiology, Smithsonian Institution, Washington, DC 20560, USA.
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Pálfy J. Volcanism of the Central Atlantic Magmatic Province as a potential driving force in the end-Triassic mass extinction. THE CENTRAL ATLANTIC MAGMATIC PROVINCE: INSIGHTS FROM FRAGMENTS OF PANGEA 2003. [DOI: 10.1029/136gm014] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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White RV. Earth's biggest 'whodunnit': unravelling the clues in the case of the end-Permian mass extinction. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2002; 360:2963-2985. [PMID: 12626276 DOI: 10.1098/rsta.2002.1097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The mass extinction that occurred at the end of the Permian period, 250 million years ago, was the most devastating loss of life that Earth has ever experienced. It is estimated that ca. 96% of marine species were wiped out and land plants, reptiles, amphibians and insects also suffered. The causes of this catastrophic event are currently a topic of intense debate. The geological record points to significant environmental disturbances, for example, global warming and stagnation of ocean water. A key issue is whether the Earth's feedback mechanisms can become unstable on their own, or whether some forcing is required to precipitate a catastrophe of this magnitude. A prime suspect for pushing Earth's systems into a critical condition is massive end-Permian Siberian volcanism, which would have pumped large quantities of carbon dioxide and toxic gases into the atmosphere. Recently, it has been postulated that Earth was also the victim of a bolide impact at this time. If further research substantiates this claim, it raises some intriguing questions. The Cretaceous-Tertiary mass extinction, 65 million years ago, was contemporaneous with both an impact and massive volcanism. Are both types of calamity necessary to drive Earth to the brink of faunal cataclysm? We do not presently have enough pieces of the jigsaw to solve the mystery of the end-Permian extinction, but the forensic work continues.
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Affiliation(s)
- Rosalind V White
- Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK.
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Eldhom O, Coffin MF. Large igneous provinces and plate tectonics. GEOPHYSICAL MONOGRAPH SERIES 2000. [DOI: 10.1029/gm121p0309] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Affiliation(s)
- Paul E. Olsen
- The author is at the Lamont Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA
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Chung SL, Jahn BM, Genyao W, Lo CH, Bolin C. The Emeishan flood basalt in SW China: A mantle plume initiation model and its connection with continental breakup and mass extinction at the Permian-Triassic Boundary. MANTLE DYNAMICS AND PLATE INTERACTIONS IN EAST ASIA 1998. [DOI: 10.1029/gd027p0047] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Timing of the Ethiopian flood basalt event and implications for plume birth and global change. Nature 1997. [DOI: 10.1038/39853] [Citation(s) in RCA: 473] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Duncan RA, Hooper PR, Rehacek J, Marsh JS, Duncan AR. The timing and duration of the Karoo igneous event, southern Gondwana. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jb00972] [Citation(s) in RCA: 396] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kuo BY, Wu KY. Global shear velocity heterogeneities in the D″ layer: Inversion fromSd-SKSdifferential travel times. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jb00305] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Vermeij GJ, Dorritie D. Late Permian Extinctions. Science 1996. [DOI: 10.1126/science.274.5292.1550.a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Glasby GP, Kunzendorf H. Multiple factors in the origin of the Cretaceous/Tertiary boundary: the role of environmental stress and Deccan Trap volcanism. GEOLOGISCHE RUNDSCHAU : ZEITSCHRIFT FUR ALLGEMEINE GEOLOGIE 1996; 85:191-210. [PMID: 11543126 DOI: 10.1007/bf02422228] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A review of the scenarios for the Cretaceous/ Tertiary (K/T) boundary event is presented and a coherent hypothesis for the origin of the event is formulated. Many scientists now accept that the event was caused by a meteorite impact at Chicxulub in the Yucatan Peninsula, Mexico. Our investigations show that the oceans were already stressed by the end of the Late Cretaceous as a result of the long-term drop in atmospheric CO2, the long-term drop in sea level and the frequent development of oceanic anoxia. Extinction of some marine species was already occurring several million years prior to the K/T boundary. The biota were therefore susceptible to change. The eruption of the Deccan Traps, which began at 66.2 Ma, coincides with the K/T boundary events. It erupted huge quantities of H2SO4, HCl, CO2, dust and soot into the atmosphere and led to a significant drop in sea level and marked changes in ocean temperature. The result was a major reduction in oceanic productivity and the creation of an almost dead ocean. The volcanism lasted almost 0.7 m.y. Extinction of biological species was graded and appeared to correlate with the main eruptive events. Elements such as Ir were incorporated into the volcanic ash, possibly on soot particles. This horizon accumulated under anoxic conditions in local depressions and became the marker horizon for the K/T boundary. An oxidation front penetrated this horizon leading to the redistribution of elements. The eruption of the Deccan Traps is the largest volcanic event since the Permian-Triassic event at 245 Ma. It followed a period of 36 m.y. in which the earth's magnetic field failed to reverse. Instabilities in the mantle are thought to be responsible for this eruption and therefore for the K/T event. We therefore believe that the K/T event can be explained in terms of the effects of the Deccan volcanism on an already stressed biosphere. The meteorite impact at Chicxulub took place after the onset of Deccan volcanism. It probably played a regional, rather than global, role in the K/T extinction.
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Affiliation(s)
- G P Glasby
- Department of Earth Sciences, University of Sheffield, England
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Visscher H, Brinkhuis H, Dilcher DL, Elsik WC, Eshet Y, Looy CV, Rampino MR, Traverse A. The terminal Paleozoic fungal event: evidence of terrestrial ecosystem destabilization and collapse. Proc Natl Acad Sci U S A 1996; 93:2155-8. [PMID: 11607638 PMCID: PMC39926 DOI: 10.1073/pnas.93.5.2155] [Citation(s) in RCA: 186] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Because of its prominent role in global biomass storage, land vegetation is the most obvious biota to be investigated for records of dramatic ecologic crisis in Earth history. There is accumulating evidence that, throughout the world, sedimentary organic matter preserved in latest Permian deposits is characterized by unparalleled abundances of fungal remains, irrespective of depositional environment (marine, lacustrine, fluviatile), floral provinciality, and climatic zonation. This fungal event can be considered to reflect excessive dieback of arboreous vegetation, effecting destabilization and subsequent collapse of terrestrial ecosystems with concomitant loss of standing biomass. Such a scenario is in harmony with predictions that the Permian-Triassic ecologic crisis was triggered by the effects of severe changes in atmospheric chemistry arising from the rapid eruption of the Siberian Traps flood basalts.
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Affiliation(s)
- H Visscher
- Laboratory of Paleobotany and Palynology, Utrecht University, Utrecht, The Netherlands
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Poornachandra Rao G, Mallikharjuna Rao J, Subba Rao M. Palaeomagnetic and geochemical characteristics of the Rajmahal Traps, eastern India. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/0743-9547(96)00012-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Review. Cladistics 1992; 8:391-398. [PMID: 34929962 DOI: 10.1111/j.1096-0031.1992.tb00081.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Book review in this article: Introdução histórica à biologia comparada com especial referência à biogeografia, vols. I, II e III (Historical introduction to comparative biology with special reference to biogeography-(Vols. I, II and III) (In Portuguese) by Nelson Papavero. New concepts in global tectonics edited by Sankar Chatterjee and Nicholas Hotton, III.
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Renne PR, Ernesto M, Pacca IG, Coe RS, Glen JM, Prévot M, Perrin M. The Age of Parana Flood Volcanism, Rifting of Gondwanaland, and the Jurassic-Cretaceous Boundary. Science 1992; 258:975-9. [PMID: 17794593 DOI: 10.1126/science.258.5084.975] [Citation(s) in RCA: 361] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Paraná-Etendeka flood volcanic event produced approximately 1.5 x 10(6) cubic kilometers of volcanic rocks, ranging from basalts to rhyolites, before the separation of South America and Africa during the Cretaceous period. New (40)Ar/(39)Ar data combined with earlier paleomagnetic results indicate that Paraná flood volcanism in southern Brazil began at 133 +/- 1 million years ago and lasted less than 1 million years. The implied mean eruption rate on the order of 1.5 cubic kilometers per year is consistent with a mantle plume origin for the event and is comparable to eruption rates determined for other well-documented continental flood volcanic events. Paraná flood volcanism occurred before the initiation of sea floor spreading in the South Atlantic and was probably precipitated by uplift and weakening of the lithosphere by the Tristan da Cunha plume. The Parana event postdates most current estimates for the age of the faunal mass extinction associated with the Jurassic-Cretaceous boundary.
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Hawkesworth CJ, Gallagher K, Kelley S, Mantovani M, Peate DW, Regelous M, Rogers NW. Paraná magmatism and the opening of the South Atlantic. ACTA ACUST UNITED AC 1992. [DOI: 10.1144/gsl.sp.1992.068.01.14] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Renne PR, Basu AR. Rapid Eruption of the Siberian Traps Flood Basalts at the Permo-Triassic Boundary. Science 1991; 253:176-9. [PMID: 17779134 DOI: 10.1126/science.253.5016.176] [Citation(s) in RCA: 298] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Siberian Traps represent one of the most voluminous flood basalt provinces on Earth. Laser-heating (40)Ar/(39)Ar data indicate that the bulk of these basalts was erupted over an extremely short time interval (900,000 +/- 800,000 years) beginning at about 248 million years ago at mean eruption rates of greater than 1.3 cubic kilometers per year. Such rates are consistent with a mantle plume origin. Magmatism was not associated with significant lithospheric rifting; thus, mantle decompression resulting from rifting was probably not the primary cause of widespread melting. Inception of Siberian Traps volcanism coincided (within uncertainty) with a profound faunal mass extinction at the Permo-Triassic boundary 249 +/- 4 million years ago; these data thus leave open the question of a genetic relation between the two events.
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Caldeira K, Rampino MR. Carbon dioxide emissions from Deccan volcanism and a K/T boundary greenhouse effect. GEOPHYSICAL RESEARCH LETTERS 1990; 17:1299-1302. [PMID: 11538480 DOI: 10.1029/gl017i009p01299] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A greenhouse warming caused by increased emissions of carbon dioxide from the Deccan Traps volcanism has been suggested as the cause of the terminal Cretaceous extinctions on land and in the sea. We estimate total eruptive and noneruptive CO2 output by the Deccan eruptions (from 6 to 20 x 10(16) moles) over a period of several hundred thousand years based on best estimates of the CO2 weight fraction of the original basalts and basaltic melts, the fraction of CO2 degassed, and the volume of the Deccan Traps eruptions. Results of a model designed to estimate the effects of increased CO2 on climate and ocean chemistry suggest that increases in atmospheric pCO2 due to Deccan Traps CO2 emissions would have been less than 75 ppm, leading to a predicted global warming of less than 1 degree C over several hundred thousand years. We conclude that the direct climate effects of CO2 emissions from the Deccan eruptions would have been too weak to be an important factor in the end-Cretaceous mass extinctions.
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Affiliation(s)
- K Caldeira
- Department of Applied Science, New York University, USA
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Abstract
Continental flood basalt eruptions have resulted in sudden and massive accumulations of basaltic lavas in excess of any contemporary volcanic processes. The largest flood basalt events mark the earliest volcanic activity of many major hot spots, which are thought to result from deep mantle plumes. The relative volumes of melt and eruption rates of flood basalts and hot spots as well as their temporal and spatial relations can be explained by a model of mantle plume initiation: Flood basalts represent plume "heads" and hot spots represent continuing magmatism associated with the remaining plume conduit or "tail." Continental rifting is not required, although it commonly follows flood basalt volcanism, and flood basalt provinces may occur as a natural consequence of the initiation of hot-spot activity in ocean basins as well as on continents.
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