Lake Titicaca is a high-elevation (3812 m) lake in the tropical Andes of Bolivia and Peru and was drilled in April/May 2001 using the GLAD 800 drilling platform and coring system (Figure 1). This site is critical for reconstructing the history of the South American summer monsoon system and how long-term variation in effective moisture in the tropical Andes is affected by variation of global-scale glacial boundary conditions, orbitally produced changes in seasonal insolation, and changes in tropical Pacific and/or Atlantic sea-surface temperature. Over 625 m of mud was recovered from paired overlapping holes in three locations. The longest recovered sequence spans 136 m and consists of alternations between two primary lithologic units, indicative of four major glacial stages and the intervening interglacials.
Figure 1 – GLAD800 drilling platform on Lake Titicaca
Generally, the intervals of increased glaciation were periods when Lake Titicaca was deep and fresh and therefore times of high effective moisture and likely high precipitation (based on calcium carbonate concentrations, diatom stratigraphy, and d13C isotopic measurements on bulk organic carbon). A chronology based on radiocarbon, U-series ages on aragonite laminae, and tuning to the Vostok CO2 record suggests that the drilled sequence extends over approximately the last 370,000 years. Extrapolation of the radiocarbon chronology suggests that the most recent period of ice expansion in the cordillera surrounding the lake began approximately 60,000 14C yr BP, following a major dry interval. A series of U-series dates on discrete aragonite layers suggests that the penultimate low stand of Lake Titicaca, rather than dating to the last summer solar minimum (~32,000 yr BP), is coincident with MIS5e, the penultimate interglacial stage (~125,000 yr BP). This suggests that the water balance of the lake is as strongly influenced by global-scale (an tropical) temperature changes and boundary conditions as by precession forcing of the South American summer monsoon.
Figure 2 – Drilling log and lithology of Lake Titicaca borehole 2B.
Baker, P.A. and S.C. Fritz. High-resolution records and mechanisms of climate variability in tropical South America…and beyond. IODP-ICDP Workshop: Acquiring high to ultra-high resolution geological records of past climate change by scientific drilling, October 2008, Potsdam, Germany.
Baker, P.A., S.C. Fritz, C.A. Rigsby, S.A Burns, K.Coley, E. Ekdahl. “Millennial Climate Variability in Tropical South America”. American Geophysical Union, San Francisco, December 2005.
Baker, P.A., S.C. Fritz, G.O. Seltzer, & C. Rigsby. Tropical climate dynamics in the South American Altiplano. AGU Annual Meeting, San Francisco, December 2003.
Baker, P.A., S.C. Fritz, G.O. Seltzer, C. Rigsby, S. Cross, M. Grove, A. Ballantyne. “Climates of tropical South America: past, present, and future” European Geophysical Union, Vienna, April 2007.
Baker, P.A., S.C. Fritz, G.O. Seltzer, K. Arnold, & P. Tapia. Geochemical and diatom records of hydrologic variability in the tropical Andes during the late Quaternary from drill cores of Lake Titicaca. AGU, San Francisco, December 2002. EOS Trans. 83: F896.
Baker, PA, S C Fritz, G O Seltzer, A P Ballantyne, C A Rigsby. The Terrestrial Paleoclimatic Record of the Late Quaternary as Revealed by Drilling Lake Titicaca, Peru/Bolivia. American Geophysical Union, San Francisco, December 2004
Ekdahl, E J, S C Fritz, L R Stevens, P A Baker, G O Seltzer. A High-Resolution Biogenic Silica Record From Lake Titicaca, Peru-Bolivia: South American Millennial-Scale Climate Variability From 18-60 Kya. American Geophysical Union, San Francisco, December 2004.
Ekdahl, E., Fritz, S.C., Baker, P.A., Burns, S.A., Coley, K., Rigsby, C.A. “Multi-Decadal to Millennial Scale Holocene Hydrologic Variation in the Southern Hemisphere Tropics of South America”. American Geophysical Union, San Francisco, December 2005.
Fritz, S.C., P.A. Baker, E. Ekdahl, S. Burns, “Holocene multi-decadal to millennial-scale hydrologic variability on the South American Altiplano”, American Geophysical Union, San Francisco, December 2006.
Fritz, S.C., P.A. Baker, G.O. Seltzer, A. Ballantyne, P. Tapia, H. Cheng, R.L. Edwards. 2007. Quaternary glaciation and hydrologic variation in the South American tropics as reconstructed from the Lake Titicaca drilling project. Quaternary Research 68: 410-420.
Fritz, S.C., P.A. Baker, G.O. Seltzer, E. Ekdahl, “Glaciation and hydrologic variation in the South American tropics during the last 400,000 yr”. American Geophysical Union, San Francisco, December 2005.
Fritz, S.C., P.A.Baker, G.O. Seltzer. “Late Quaternary hydrologic variability in the southern tropical Andes and its relationship to the adjoining Amazon Basin and major climate drivers”, International Quaternary Association Congress, Cairns, Australia, August 2007.
Fritz, S.C., T. Johnson, P.A. Baker, S. Colman, W. Dean, J. Peck. 2006. Large-lake drilling projects supported by the US National Science Foundation Earth Systems History Program. PAGES News 14: 19-20.
Seltzer, G.O., P.A. Baker, S.C. Fritz, D. Rodbell, & B. Valero. The record of tropical glaciation from drill cores from Lake Titicaca, Bolivia/Peru. Geological Society of America, Seattle, November 2003.
Seltzer, G.O., P.A. Baker, S.C.Fritz, K. Arnold, A. Ballantine, P. Tapia, & C. Veliz. A long record of tropical glaciation and climate change in drill cores from Lake Titicaca. AGU, San Francisco, December 2001. EOS Trans. 82: F757.
Seltzer, G.O., S.C. Fritz, P.A. Baker. A >100 kyr record of glaciation from the southern tropical Andes. AGU San Francisco, December 2002. EOS Trans. 83: F896.
Partial listing of presentations:
Fritz, S.C. – Invited University presentations:
2008: Braunschweig University (Geology)
2007: Kansas State University (Geology), University of Adelaide, Australia (Geography), University of Edinburgh (Geosciences), CEREGE, Aix-en-Provence, France
2006: Queens University, Kingston, ON (Biological Sciences), University (Environmental Sciences), Louisiana State University (Geology)
2005: Lehigh University (Earth & Environmental Sciences), Iowa State University (Earth & Atmospheric Sciences)
University of Iowa (Geology), Geological Survey of Denmark and Greenland