Hydrologic variation during the last 170,000 years in the southern hemisphere tropics of South America
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Despite the hypothesized importance of the tropics in the global climate system, few tropical paleoclimatic records extend to periods earlier than the last glacial maximum (LGM), about 20,000 years before present. We present a well-dated 170,000-year time series of hydrologic variation from the southern hemisphere tropics of South America that extends from modern times through most of the penultimate glacial period. Alternating mud and salt units in a core from Salar de Uyuni, Bolivia reflect alternations between wet and dry periods. The most striking feature of the sequence is that the duration of paleolakes increased in the late Quaternary. This change may reflect increased precipitation, geomorphic or tectonic processes that affected basin hydrology, or some combination of both. The dominance of salt between 170,000 and 140,000 yr ago indicates that much of the penultimate glacial period was dry, in contrast to wet conditions in the LGM. Our analyses also suggest that the relative influence of insolation forcing on regional moisture budgets may have been stronger during the past 50,000 years than in earlier times. © 2003 University of Washington. All rights reserved.
Published Version (Please cite this version)10.1016/j.yqres.2003.08.007
Publication InfoFritz, SC; Baker, PA; Lowenstein, TK; Seltzer, GO; Rigsby, CA; Dwyer, GS; ... Luo, S (2004). Hydrologic variation during the last 170,000 years in the southern hemisphere tropics of South America. Quaternary Research, 61(1). pp. 95-104. 10.1016/j.yqres.2003.08.007. Retrieved from https://hdl.handle.net/10161/6625.
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Professor of Earth and Ocean Sciences in the Nicholas School of the Environment
For the past several years, I have been pursuing the goal of understanding climate change on time-scales from decades to millions of years. I am particularly interested in what forces natural climate variability, how past climates have influenced the ecology and diversity of organisms in the tropics, as well as how climate change and other human activities will affect the eventual fate of these organisms.
Sr. Research Scientist and Instructor in Earth and Ocean Sciences
Dwyer's experience lies in the development of tracers and indicators of environmental change, and their application to modern and ancient environmental systems. Research areas include paleoceanography, paleoclimatology, carbonate sedimentology, marine geology and environmental geochemistry.
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