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Molybdenum isotopic evidence for oxic marine conditions during the latest Permian extinction

Citation

Proemse, BC and Grasby, SE and Wieser, ME and Mayer, B and Beauchamp, B, Molybdenum isotopic evidence for oxic marine conditions during the latest Permian extinction, Geology, 41, (9) pp. 967-970. ISSN 0091-7613 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 Geological Society of America

DOI: doi:10.1130/G34466.1

Abstract

The latest Permian extinction (LPE), ca. 252 Ma, represents the most severe extinction event in Earth's history. The cause is still debated, but widespread marine anoxic to euxinic (H2S rich) conditions, from deep to shallow water environments, are commonly suggested. As a proxy for marine oxygen levels, we analyzed δ98/95Mo of two LPE sections that represent a gradient in water depth on the northwest margin of Pangea. Results from deep-water slope environments show a large shift in δ98/95Mo values from −2.02 to +2.23 at the extinction horizon, consistent with onset of euxinic conditions. In contrast, sub-storm wave base shelf environments show little change in the molybdenum isotopic composition (−1.34 to +0.05), indicating ongoing oxic conditions across the LPE. These results indicate that areas of the continental shelf of northwest Pangea underwent mass extinction under oxic conditions throughout the LPE event, and that shallow-water anoxia was therefore not a global phenomenon.

Item Details

Item Type:Refereed Article
Keywords:ocean anoxia, Permian Triassic extinction, Molybdenum isotopes
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Isotope Geochemistry
Objective Division:Environment
Objective Group:Physical and Chemical Conditions of Water
Objective Field:Physical and Chemical Conditions of Water in Marine Environments
Author:Proemse, BC (Dr Bernadette Proemse)
ID Code:98036
Year Published:2013
Web of Science® Times Cited:20
Deposited By:Zoology
Deposited On:2015-01-29
Last Modified:2015-02-03
Downloads:0

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