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 δ^98/95Mo 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 δ^98/95Mo 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 Type:	Refereed Article
Keywords:	ocean anoxia, Permian Triassic extinction, Molybdenum isotopes
Research Division:	Earth Sciences
Research Group:	Geochemistry
Research Field:	Isotope geochemistry
Objective Division:	Environmental Management
Objective Group:	Marine systems and management
Objective Field:	Measurement and assessment of marine water quality and condition
UTAS Author:	Proemse, BC (Dr Bernadette Proemse)
ID Code:	98036
Year Published:	2013
Web of Science® Times Cited:	54
Deposited By:	Zoology
Deposited On:	2015-01-29
Last Modified:	2017-11-02
Downloads:	0