Geological Society of America

3 Tropical Climate and Paleoclimate

Monday, 21 March 2016
8:00 AM - 12:00 PM
Meeting Room 1

COMBINED INFLUENCE OF AUSTRAL SUMMER INSOLATION AND MILLENNIAL-SCALE ABRUPT EVENTS ON THE SOUTH AMERICAN MONSOON SYSTEM

Paper number: 3-4
Program: Theme Sessions
Time: 8:45 AM – 9:05 AM

Authors

Valdir Felipe Novello Presenting Author
Universidade de São Paulo, São Paulo
Mathias Vuille
University at Albany, SUNY, Albany, NY
Francisco W. Cruz
Universidade de São Paulo, São Paulo, São Paulo
Hai Cheng
University of Minnesota, Minneapolis, MN
Lawrence Edwards
University of Minnesota, Minneapolis, MN

Abstract

The South American Monsoon System (SAMS) and the Inter-Tropical Convergence Zone (ITCZ) are the two most important circulation systems affecting climate over tropical South America (SA). Both of these convective systems are closely related to one another, and are sensitive to changes in summer insolation and Northern Hemisphere (NH) boundary conditions. While an increasing number of paleoclimatic archives related to SAMS precipitation have recently been published, most of these paleoclimate reconstructions are located along the eastern slope of the tropical Andes or in southeastern SA. In central SA, most proxy records consist of pollen-based vegetation reconstructions, but these show significant disagreements with the precipitation records to the east and west. Here we present a new high-resolution oxygen isotope record (JAR) of the SAMS, extending back to 33.000 BP from speleothems collected in the southern Pantanal, central SA. Our record shows a competing influence of austral summer insolation with millennial-scale abrupt events during the transition from the Last Glacial Maximum (LGM) to the Holocene and helps explain the divergent results obtained from some paleoclimate records.

Geological Society of America Abstracts with Programs. Vol. 48, No. 1

doi: 10.1130/abs/2016NE-272799

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