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.
Bibliographical noteFunding Information:
We thank the staff and associates of DOSECC, D. Schnurrenberger, G. Mollericon, K. Arnold, C. Veliz, J. Broda, G. Salas, J. Villanueva, J. Valdez, J. Siles and S. Mamani for assistance with drilling and field work and Autoridad Autonoma de Lago Titicaca; and the Bolivian Navy, J. Sangines, DOSECC and Crillon Tours for assistance with logistics. K. Arnold, J. Smith, J. Garland, D. Schnurrenberger, A. Myrbo, A. Noren and other staff of LacCore assisted with core sampling and laboratory work. Funded by U.S. National Science Foundation (ESH) and ICDP grants to PAB, SCF and GOS.
- Lake Titicaca
- South America