Geological Society of America

1 Climate Reconstructions from Cave Deposits

Monday, 16 April 2018
8:00 AM - 12:00 PM
Benton Auditorium

STALAGMITE RECORDS FROM WEST-CENTRAL PORTUGAL TEST LINKS BETWEEN NORTH ATLANTIC PALEOCEANOGRAPHY AND IBERIAN CONTINENTAL CLIMATE OVER THE PAST TWO GLACIAL CYCLES

Paper number: 1-1
Program: Theme Sessions
Time: 8:00 AM – 8:20 AM

Authors

Rhawn Denniston Presenting Author
Cornell College, Mount Vernon, IA
Sebastian Breitenbach
Ruhr University Bochum, Bochum
Caroline Ummenhofer
Woods Hole Oceanographic Institution, Falmouth, MA
Francisco Regala
Associação de Estudos Subterrâneos e Defesa do Ambiente, Torres Vedras
Michael M. Benedetti
University of North Carolina Wilmington, Wilmington, NC
Nuno Bicho
ICArEHB, Universidade do Algarve, Faro
Amanda N. Houts
The University of New Hampshire, Durham, NH
Yemane Asmerom
University of New Mexico, Albuquerque, NM
Alan D. Wanamaker
Iowa State University, Ames, IA
Jonathan A. Haws
University of Louisville, Louisville, KY
Victor Polyak
University of New Mexico, Albuquerque, NM
Diana L. Thatcher
Iowa State University, Ames, IA
Setsen Altan-Ochir
Cornell College, Mount Vernon, IA
Alyssa Borowske
University of Connecticut, Stoors, CA

Abstract

Links between Iberian hydroclimate and North Atlantic sea surface temperature (SST) have been carefully examined across the past several glacial cycles using marine sediment and pollen grains co-deposited on the Portuguese continental margin. Few directly dated, independent continental records of Iberian climate spanning similar time intervals have been identified, however. We present a high-resolution, multi-proxy (isotopic ratios of carbon, oxygen, and uranium, as well as growth intervals) record of hydroclimate from several stalagmites obtained from two caves (Buraca Gloriosa and Gruta do Casal da Lebre) in west-central Portugal that span the majority of the last two glacial cycles (~230 ka). At orbital and millennial scales, stalagmite-based proxies of hydroclimate covaried with SST, with positive carbon isotope excursions and/or growth hiatuses indicating reduced effective moisture coincident with colder conditions with ice-rafted debris events and Greenland stadials. These findings agree well with reconstructions of continental climate derived from pollen extracted from Iberian margin marine sediments. However, the Portuguese stalagmite record also reveals intervals during which the magnitudes of hydroclimate changes may have been somewhat decoupled from SST.

Geological Society of America Abstracts with Programs. Vol. 50, No. 4

doi: 10.1130/abs/2018NC-311401

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