T247 Volcanism, Impacts, and Phanerozoic Mass Extinctions: Discovering a Common Cause and Planning for the 6th Mass Extinction I

Wednesday, 25 September 2019
8:00 AM - 12:00 PM
Room 227ABC, North Building

ASHLANTIC: A MULTI-PROXY APPROACH TO UNDERSTANDING THE RELATIONSHIP BETWEEN THE NORTH ATLANTIC IGNEOUS PROVINCE AND THE PALEOCENE-EOCENE THERMAL MAXIMUM

Paper number: T247-13
Program: Technical Sessions
Time: 11:05 AM – 11:25 AM

Authors

Abstract

There is a striking temporal correlation between the emplacement of large igneous provinces (LIPs) and extreme climate change events in the sedimentary record. One such example is the Paleocene-Eocene Thermal Maximum (PETM), an extreme (5-6 °C) and rapid (<20 kyr) global warming event at ~56 Ma that persisted for at least 100 kyr. The PETM coincided with a major pulse of magmatism from the North Atlantic Igneous Province (NAIP), suggesting a possible causal relationship. The island of Fur, located within Limfjorden in northwest Denmark, is an excellently preserved epicontinental shallow marine sequence from latest Paleocene to mid-Eocene times. The PETM interval is an expanded sequence with high sedimentation rates, allowing the identification of changes on a fine temporal scale. The sequence also contains over 180 distinct volcanic ash layers that originated from NAIP volcanic centers in east Greenland and northwest British Isles.

Here we present preliminary findings from Fur, spanning approximately 300 kyr from the initiation of the PETM to post-PETM strata. High precision U-Pb dating of magmatic zircons helps constrain the timing and duration of the PETM, as well as local sedimentation rates. Detailed chemostratigraphic logs, such as total organic carbon (TOC) δ13C analyses, are used to define the onset and duration of the PETM, providing a geochronological framework for numerous environmental and volcanic proxies. Inorganic proxies, organic biomarkers, and the organic paleothermometer TEX86 suggest a significant increase in sea surface temperatures and ocean anoxia during the onset of the PETM. Weathering proxies such as clay fractions and lithium isotopes indicate a rapid increase in silicate weathering rates concurrent with this temperature rise. Volcanic proxies such as mercury anomalies and visible tephra layers show that explosive volcanism was active at the onset of the PETM, suggesting that the NAIP played a primary role in the cause of this extreme climate warming event.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-341320

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