Geological Society of America

38 Undergraduate Research I (Posters)

Saturday, 21 March 2020
8:00 AM - 12:00 PM
Grand Ballroom A–D

DID THE COLUMBIA RIVER FLOOD BASALTS INITIATE THE MIOCENE CLIMATE OPTIMUM? CONSTRAINING THE TIMING OF LIP VOLCANISM AND CLIMATE CHANGE USING SEDIMENTARY MERCURY CONCENTRATIONS

Paper number: 38-9
Program: Theme Sessions
Time: 8:00 AM – 12:00 PM

Authors

Heather Grotzinger Presenting Author
Amherst College Geology, Amherst, MA
Hannah Runyon
Colorado College, Colorado Springs, CO
John P. Grotzinger
California Institute of Technology, Pasadena, CA
David Jones
Amherst College, Amherst, MA
Andrew Knoll
Harvard Univ, Cambridge, MA
Christine Y. Chen
Massachusetts Institute of Technology, Cambridge, MA
Athena Eyster
MITEAPS, Cambridge, MA
Karol Faehnrich
Dartmouth College, Hanover, NH
Jordon Hemingway
Harvard University, Cambridge, MA
Jennifer J. Kasbohm
Yale University, New Haven, CT
Paula Mateo
California Institute of Technology, Pasadena, CA
Alessandra Petrucciani
Università Politecnica delle Marche, Ancona
Daniela Osorio Rodriguez
California Institute of Technology, Pasadena, CA

Abstract

The extent to which large igneous province volcanism has driven global climate change throughout the Phanerozoic Eon has been debated. Release of CO₂ during the eruption of the Columbia River Flood Basalts (CRFB), the youngest large igneous province (LIP), is hypothesized to have initiated the Miocene Climate Optimum (MCO), a period of global warming 3-4°C above baseline during the Miocene. However, recent high precision geochronology dates the onset of CRFB volcanism as occurring ~100 kyr after the initiation of the MCO, calling into question the extent to which this LIP volcanism triggered global climate change. Mercury concentrations in sedimentary rocks can be used as a proxy for major volcanic events. Volcanic emissions were a major source of Hg in the pre-anthropogenic Hg cycle and this volcanic Hg can be preserved in sedimentary rocks. Here we report new Hg concentration data from stratigraphic sections of the Majella carbonate platform in the central Apennines (Italy) along with stable isotope data (δ¹³C and δ¹⁸O) and biostratigraphy of the MCO. We also compare the record of Hg in shallow and deep sections of the ramp to better understand the paleoenvironmental conditions that affect its preservation. Correlating Hg concentrations to the global record of the Miocene Climate Optimum will improve the chronology of these events leading to a more refined timeline that can be used to test cause and effect relationships between large igneous province volcanism and global climate change.

Geological Society of America Abstracts with Programs. Vol. 52, No. 2

doi: 10.1130/abs/2020SE-344911

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