T226 Cushman Foundation Symposium: Microfossil Mayhem—Murder, Misfortune, and More

Tuesday, 24 October 2017
1:30 PM - 5:30 PM
Room 611

RECONSTRUCTION OF LATE HOLOCENE HYDROCLIMATE AND ENVIRONMENTAL CHANGE IN SOUTHERN CENTRAL AMERICA WITH AN EMPHASIS ON THE TERMINAL CLASSIC DROUGHT (TCD)

Paper number: T226-10
Program: Technical Sessions
Time: 3:50 PM – 4:05 PM

Authors

Abstract

In Central America, the Terminal Classic Drought (TCD) was defined by a series of moderate to severe droughts that took place between ~750 and 1100 CE. However, to-date, we have a limited understanding of how thermal conditions varied during the TCD and if changes in vegetation and hydrology were coeval with an altered thermal regime in this region. Lake sediment cores recovered from two, high-elevation, glacially-formed lakes in highlands of central Costa Rica, were analyzed for sub-fossil chironomids, charcoal and sediment geochemistry (C%, N%, δ13C, and C/N ratios). Variations in the abundance of chironomid indicator taxa, e.g. Procladius and Psectrocladius, in conjunction with increases in charcoal concentration and fluctuations in δ13C, indicative of the expansion of C4 vegetation, suggest that the TCD (~830-1100 CE) in the central highlands of Costa Rica was characterized by an extended interval of cool, dry conditions and more frequent fires. The results of this study are used to assess the hypothesis that a cooling of the tropical Atlantic and a strengthened North Atlantic Subtropical High can provide a dynamical explanation for the multi-decadal droughts that characterizes the TCD interval in Central America.

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

doi: 10.1130/abs/2017AM-297071

© Copyright 2017 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.