T81 Deep-Time Carbon Cycles, Redox Changes, and the Evolution of the Biosphere I

Tuesday, 27 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

CONTRASTING RESPONSES OF THE GLOBAL CARBON CYCLE DURING THE END-PERMIAN AND THE END-GUADALUPIAN MASS EXTINCTIONS

Paper number: T81-9
Program: Technical Sessions
Time: 3:20 PM – 3:35 PM

Authors

Abstract

Two mass extinction events occurred during the end-Guadalupian (ca. 259.1 Ma) and the end-Permian (ca. 251.9Ma). The duration of these two events, however, varies drastically: the end-Guadalupian mass extinction (EGME) lasted for >2 Myr and the end-Permian mass extinction (EPME) persisted for less than ~61 kyr. Each event is associated with a Large Igneous Province (LIP) — the Emeishan LIP associated with the EGME and the Siberian Traps LIP linked to the EPME.Both events are also characterized by negative carbon isotope excursions in marine carbonates deposited globally. The behavior of the carbon cycle during these two events has striking contrasts and the rates of silicate weathering that removes the carbon dioxide from the atmosphere also differ, which lead to different temperature responses following each event. To quantify the carbon emission and sequestration rate of the EGME and the EPME, we performed carbon cycle modelsimulations using a relatively simple box model LOSCAR and an Earth system model of intermediate complexity cGENIE. The silicate weathering rates in these models are parameterized to respond to pCO2 (and/or temperature, and/or runoff). Ourmodeling work allows for quantitative estimates of both the long- and short-term carbon cycle response to a rapid carbon emission associated with LIPs.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-357875

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