PARENT SESSION
Contributed Oral Session 77: Paleoecology
Wednesday, August 10, 8:00 AM - 11:30 AM, Meeting Room 515 A, Level 5, Palais des congrès de Montréal
Difference in community composition between and within the Holocene and MIS 5e in two records from Lake Titicaca (Bolivia/Peru).
Hanselman, Jennifer1, Bush, Mark1, Gosling, William1, 1 Florida Institute of Technology, Melbourne, Florida, U.S.A.
ABSTRACT- Lake Titicaca (16° to 17.50°S, 68.5° to 70°W; 3810m) is the highest great lake in the world, and its deep sediments provide an opportunity to investigate long-term climate change across glacial cycles. Analysis of fossil pollen and spores from the main basin of Titicaca and its adjoining basin to the south, Huinaimarca, revealed significant changes in pollen concentration from the glacial to interglacial periods. Both records demonstrated the difference in plant community composition between and within the Holocene and the previous interglacial, MIS 5e. The Holocene is mainly represented by Poaceae and Asteraceae types while MIS 5e was dominated by Chenopodiaceae, suggesting MIS 5e was a warm and dry interglacial. Both the early and late sections of interglacial MIS 5e and the early Holocene had increased representation of Polylepis during transitional climate phases in the records. Particular attention should be paid to Polylepis, as its unique physiology allows it to live above the tree line and it has been suggested that prior to human occupation it dominated the high elevation landscape of the Andes. These records provide evidence that interglacials support distinct floras and Holocene floras are not necessarily good analogs for earlier interglacial communities.
Key words: pollen, interglacial, Polylepis, Chenopodiaceae