Geological Society of America

T283 Greenhouse to Icehouse Transition: Global Events of the Devonian, Carboniferous, and Early Permian II

Wednesday, 7 November 2018
1:30 PM - 5:30 PM
Room 140

TWO EPISODES OF CAPITANIAN (MIDDLE PERMIAN) MASS EXTINCTION LINKED TO OCEANIC ANOXIA

Paper number: T283-13
Program: Technical Sessions
Time: 4:40 PM – 4:55 PM

Authors

Huyue Song Presenting Author
China University of Geosciences, Wuhan
Hengye Wei
East China University of Technology, Nanchang
Ariel D. Anbar
Arizona State University, Tempe, AZ
Thomas J. Algeo
University of Cincinnati, Cincinnati, OH
Haijun Song
China University of Geosciences, Wuhan
Jinnan Tong
China University of Geosciences, Wuhan
Shuzhong Shen
Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing
Xinming Chen
Arizona State University, Tempe, AZ
Stephen J. Romaniello
Arizona State University, Tempe, AZ
Yuanyuan Zhu
Wuhan
Huasheng Shan
China University of Geosciences, Wuhan

Abstract

The Capitanian (late Middle Permian) mass extinction was a major Phanerozoic biocrisis yet its timing and causation remain poorly understood. Here, we generated a high-resolution U-isotopic (δ²³⁸U) profile for the mid-Capitanian to lower Wuchiapingian of the Penglaitan section (Middle/Upper Permian GSSP) to explore the causal relationship between the mass extinction and contemporaneous oceanic anoxic events (OAEs). This profile documents two distinct negative δ²³⁸U excursions, the first recording the mid-Capitanian OAE-C1 and the second the end-Capitanian OAE-C2. Box modeling indicates that the anoxic/euxinic sink for seawater U increased from <40 % to >80 % of the total U flux during these OAEs. Each of these OAEs coincided with a mass extinction pulse and a positive δ¹³C excursion and volcanic eruptions of the Emeishan LIP. We propose that volcanic eruptions enhanced nutrient availability and primary productivity, resulting in positive δ¹³C excursions and oceanic anoxic events. Furthermore, each OAE coincided with a phase of biotic extinction, providing the first evidence of a causal relationship between oceanic anoxia and mass extinction during the Capitanian. Our finding challenges hypotheses based on cooling or volcanic winter scenarios for this biotic crisis.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-322004

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