Geological Society of America

T265 Lacustrine Systems across Space and Time (Posters)

Tuesday, 24 October 2017
9:00 AM - 6:30 PM
Halls 4EF

LATE HOLOCENE HYDROCLIMATE RECONSTRUCTION FROM LAKE CHICHOJ, GUATEMALA USING STABLE ISOTOPE ANALYSIS OF SEDIMENTS

Paper number: T265-3
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Peter Mortensen Presenting Author
Northern Illinois University, DeKalb, IL
Nathan Stansell
Northern Illinois University, DeKalb, IL
Byron A. Steinman
University of Minnesota Duluth, Duluth, MN
Gilles Y. Brocard
The University of Sydney, Sydney NSW
Gilles Y. Brocard
The University of Sydney, Sydney
Christopher J. Shea
University of Minnesota Duluth, Duluth, MN
Matthew Lachniet
University of Nevada Las Vegas, Las Vegas, NV

Abstract

A key impact of climate change in Central America is its effect on precipitation patterns. The isotope geochemistry of rainfall in Central America is dominated by the amount effect, with an inverse relationship existing between δ¹⁸O values of surface waters and precipitation amount. Therefore, carbonate δ¹⁸O values from lake sediments can be used to reconstruct late Holocene precipitation patterns in the region. For this study, sediment cores were collected from Lake Chichoj in central Guatemala in January of 2017, along with surface water and precipitation samples. A thinly-laminated core ~2.8 m long, spanning the past ~1000 years was obtained, and sampled for authigenic carbonates at 2 mm intervals. The carbonate samples were analyzed for δ¹⁸O values, yielding a high-resolution record of hydroclimate shifts over the past ~1000 years for the area. Sediment cores were also analyzed for bulk sediment geochemistry, loss-on-ignition, and magnetic susceptibility. These results provide further information regarding hydroclimates in Central America that are influenced by ocean-atmosphere interactions in both the Pacific and Atlantic basins, including the El Niño Southern-Oscillation (ENSO) and the North Atlantic Oscillation (NAO).

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-302467

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