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Quaternary glaciation and hydrologic variation in the South American tropics as reconstructed from the Lake Titicaca drilling project |
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| Authors: | Sherilyn C Fritz Paul A Baker Geoffrey O Seltzer Ashley Ballantyne Pedro Tapia Hai Cheng R Lawrence Edwards |
| Institution: | a Department of Geosciences, University of Nebraska, Lincoln, NE 68588-0340, USA b School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0340, USA c Division of Earth and Ocean Sciences and Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, USA d Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, USA e Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455, USA |
| Abstract: | A 136-m-long drill core of sediments was recovered from tropical high-altitude Lake Titicaca, Bolivia-Peru, enabling a reconstruction of past climate that spans four cycles of regional glacial advance and retreat and that is estimated to extend continuously over the last 370,000 yr. Within the errors of the age model, the periods of regional glacial advance and retreat are concordant respectively with global glacial and interglacial stages. Periods of ice advance in the southern tropical Andes generally were periods of positive water balance, as evidenced by deeper and fresher conditions in Lake Titicaca. Conversely, reduced glaciation occurred during periods of negative water balance and shallow closed-basin conditions in the lake. The apparent coincidence of positive water balance of Lake Titicaca and glacial growth in the adjacent Andes with Northern Hemisphere ice sheet expansion implies that regional water balance and glacial mass balance are strongly influenced by global-scale temperature changes, as well as by precessional forcing of the South American summer monsoon. |
| Keywords: | Paleoclimate Lake Titicaca Andes Altiplano Bolivia Peru South America Quaternary Diatoms Isotopes Glaciation |
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