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New range data for marine invertebrate species across the early Toarcian (Early Jurassic) mass extinction

Caswell, Bryony A.; Coe, Angela L. and Cohen, Anthony S. (2009). New range data for marine invertebrate species across the early Toarcian (Early Jurassic) mass extinction. Journal of the Geological Society, 166 pp. 859–872.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1144/0016-76492008-0831
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Abstract

We have reinvestigated the marine mass extinction interval that occurred during the early Toarcian, which was a time of widespread marine anoxia. The ranges of marine benthic invertebrates are significantly altered using new observations from the Cleveland Basin, UK. Goniomya rhombifera is reported for the first time from the Whitby Mudstone Formation and together with an increased epifaunal bivalve diversity indicates a brief, relatively oxygenated period towards the end of the event. The new data, together with published results, suggest three apparent extinction horizons on a global scale; the first is just above the Pliensbachian–Toarcian boundary, and the following two are in the semicelatum ammonite Subzone. As a result of the Signor–Lipps effect there may be only one, or possibly two, true extinctions. The youngest extinction horizon coincides with the first of the abrupt carbon isotope shifts that characterize this interval, and with increases in sea surface temperature, continental weathering rates, and seawater anoxia. Pseudomytiloides dubius is the only abundant benthic macroinvertebrate during the most hostile environmental conditions but it and all other benthic species are almost entirely absent for many thousands of years immediately after each abrupt negative carbon isotope shift.

Item Type: Journal Article
Copyright Holders: 2009 The Geological Society of London
ISSN: 0016-7649
Project Funding Details:
Funded Project NameProject IDFunding Body
Not SetNot SetNERC
Academic Unit/Department: Science > Environment, Earth and Ecosystems
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 27617
Depositing User: Angela Coe
Date Deposited: 02 Feb 2011 16:50
Last Modified: 20 Mar 2014 13:52
URI: http://oro.open.ac.uk/id/eprint/27617
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