Salar de Uyuni 170KYR Drill Hole Natural Gamma Radiation Data Fritz, S.C.; Baker, P.A.; Seltzer, G.O.; Lowenstein, T.K.; Rigsby, C.A. Fritz, S.C. Baker, P.A. Seltzer, G.O. Lowenstein, T.K. Rigsby, C.A. PAGES 2k Network PAGES LOTRED SA2k earth science/paleoclimate/paleolimnology (depth,null,null,meter,null,paleolimnology,corrected,null,N,null) earth science/paleoclimate/paleolimnology (depth,null,null,meter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (gamma radiation,sediment,null,count per second,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,calendar kiloyear before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (Salar de Uyuni>LATITUDE -20.25>LONGITUDE -67.5) Despite the hypothesized importance of the tropics in the global climate system, few tropical paleoclimatic records extend to periods earlier than the last glacial maximum (LGM), about 20,000 years before present. We present a well-dated 170,000-year time series of hydrologic variation from the southern hemisphere tropics of South America that extends from modern times through most of the penultimate glacial period. Alternating mud and salt units in a core from Salar de Uyuni, Bolivia reflect alternations between wet and dry periods. The most striking feature of the sequence is that the duration of paleolakes increased in the late Quaternary. This change may reflect increased precipitation, geomorphic or tectonic processes that affected basin hydrology, or some combination of both. The dominance of salt between 170,000 and 140,000 yr ago indicates that much of the penultimate glacial period was dry, in contrast to wet conditions in the LGM. Our analyses also suggest that the relative influence of insolation forcing on regional moisture budgets may have been stronger during the past 50,000 years than in earlier times. STUDY NOTES: 188 m. cased drill hole from Salar de Uyuni salt flat, Bolivian Altiplano. Natural gamma radiation (counts per second), used as a proxy for sediment mud/salt content and therefore playa lake level. Mud units contain abundant radiogenic K, U, and Th, whereas salt units are largely nonradioactive. 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. Investigator : Lowenstein, T.K. Investigator : Rigsby, C.A. 2004-07-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/5486 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/southamerica/bolivia/salar_de_uyuni_2004.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/southamerica/bolivia/salar_de_uyuni_2004.txt English https://www.ncdc.noaa.gov/paleo/study/5486 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/southamerica/bolivia/salar_de_uyuni_2004.txt Sherilyn C Fritz, Paul A Baker, Tim K Lowenstein, Geoffrey O Seltzer, Catherine A Rigsby, Gary S Dwyer, Pedro M Tapia, Kimberly K Arnold, Teh-Lung Ku, Shangde Luo2004Hydrologic variation during the last 170,000 years in the southern hemisphere tropics of South AmericaQuaternary Research61195-10410.1016/j.yqres.2003.08.007http://www.sciencedirect.com/science/article/pii/S0033589403001327 START YEAR: 177124 cal yr BP * END YEAR: 0 cal yr BP -67.5 -20.25 -67.5 -20.25