Lake Titicaca 31,000 Year Diatom Abundance Data Fritz, S.C.; Baker, P.A.; Seltzer, G.O. Fritz, S.C. Baker, P.A. Seltzer, G.O. PAGES 2k Network PAGES LOTRED SA2k earth science/paleoclimate/paleolimnology (total benthic diatoms,null,null,percent,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (total saline diatoms,null,null,percent,null,paleolimnology,null,null,N,saline planktic) earth science/paleoclimate/paleolimnology (total freshwater diatoms,null,null,percent,null,paleolimnology,null,null,N,freshwater planktic) earth science/paleoclimate/paleolimnology (depth,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (total salinity indifferent diatoms,null,null,percent,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (Lake Titicaca Cores NE97/98>LATITUDE -16.13>LONGITUDE -69.15) A composite high-resolution diatom stratigraphy from three piston cores and one box-core in the deep sub-basin of Lake Titicaca reveals large moisture variations during the past 30 kyr in the Altiplano region. Diatom sequences indicate orbital and millennial-scale variability in water level and salinity. The pelagic freshwater diatom species Cyclotella andina and Cyclotella stelligera dominate Glacial-age sediments, suggesting that the lake was above its present outlet. Generally, wet conditions continued until 11000 cal yr BP, as indicated by high percentages of freshwater planktonic diatoms. Large pulses of benthic diatom species between about 11000 and 10000 cal yr BP suggest brief intervals of large-amplitude declines in lake level. During the early Holocene (10000-8500 cal yr BP), a freshwater diatom assemblage suggests overflowing conditions. Pelagic freshwater diatoms are replaced ca. 8500 cal yr BP by the salinity-indifferent species Cyclotella meneghiniana and by benthic taxa, indicating the beginning of lake regression. During the mid-Holocene (6000-3500 cal yr BP), the abundance of the saline taxon Chaetoceros muelleri, coupled with high abundances of epiphytic and epipelic diatoms, indicates maximum salinity and lowest lake levels in the entire 30000 year record. Lake transgression began ca. 4000 cal yr BP, and the lake achieved modern levels by about 1500 cal yr BP. These water-level changes imply changes in effective moisture, most likely resulting from large precipitation changes. Precipitation was high throughout the Last Glacial Maximum (21000-18000 cal yr BP), likely due to an enhanced South American Summer Monsoon during peak summer insolation in the Southern Hemisphere. In contrast, the mid-Holocene transition was dryer than today in association with an austral summer insolation minimum and the subsequent weakening of the summer monsoon. STUDY NOTES: Species composition data are available via the Diatom Paleolimnology Data Base Cooperative NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Fritz, S.C. Investigator : Baker, P.A. Investigator : Seltzer, G.O. 2004-07-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/5485 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/southamerica/bolivia/titicaca_2003.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/southamerica/bolivia/titicaca_2003.txt English https://www.ncdc.noaa.gov/paleo/study/5485 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/southamerica/bolivia/titicaca_2003.txt Tapia, P.M., S.C. Fritz, P.A. Baker, G.O. Seltzer, and R.B. Dunbar2003A Late Quaternary diatom record of tropical climatic history from Lake Titicaca (Peru and Bolivia)Palaeogeography, Palaeoclimatology, Palaeoecology1941-3139-164 START YEAR: 31000 cal yr BP * END YEAR: 0 cal yr BP -69.15 -16.13 -69.15 -16.13