TY - JOUR T1 - Lake-level variability in Salar de Coipasa, Bolivia during the past ∼40,000 yrAbstract JF - Quaternary Research Y1 - 2019 A1 - Nunnery, J. Andrew A1 - Fritz, Sherilyn C. A1 - Baker, Paul A. A1 - Salenbien, Wout KW - Altiplano KW - Andes KW - Paleoclimate KW - paleohydrology KW - Paleolake KW - South America AB - Various paleoclimatic records have been used to reconstruct the hydrologic history of the Altiplano, relating this history to past variability of the South American summer monsoon. Prior studies of the southern Altiplano, the location of the world’s largest salt flat, the Salar de Uyuni, and its neighbor, the Salar de Coipasa, generally agree in their reconstructions of the climate history of the past ∼24 ka. Some studies, however, have highly divergent climatic records and interpretations of earlier periods. In this study, lake-level variation was reconstructed from a ∼14-m-long sediment core from the Salar de Coipasa. These sediments span the last ∼40 ka. Lacustrine sediment accumulation was apparently continuous in the basin from ∼40 to 6 ka, with dry or very shallow conditions afterward. The fossil diatom stratigraphy and geochemical data (δ13C, δ15N, %Ca, C/N) indicate fluctuations in lake level from shallow to moderately deep, with the deepest conditions correlative with the Heinrich-1 and Younger Dryas events. The stratigraphy shows a continuous lake of variable depth and salinity during the last glacial maximum and latter stages of Marine Oxygen Isotope Stage 3 and is consistent with environmental inferences and the original chronology of a drill core from Salar de Uyuni. VL - 91 UR - https://www.cambridge.org/core/product/identifier/S0033589418001084/type/journal_article IS - 2 ER - TY - JOUR T1 - Reassessment of Lake Victoria–Upper Nile River paleohydrology from oxygen isotope records of lake-sediment cellulose JF - Geology Y1 - 2002 A1 - Beuning, K. R. M. A1 - Kelts, K. R. A1 - Russell, J. M. A1 - Wolfe, B. B. KW - cellulose KW - East Africa KW - isotope KW - oxygen KW - paleohydrology AB - Reconstruction of lake-water δ18O from analysis of cellulose δ18O in two sediment cores from Lake Victoria, East Africa, shows a large shift to lower values during the terminal Pleistocene. This shift records the transition from closed- to open-basin conditions following desiccation at the Last Glacial Maximum. Although oxygen isotope analysis of cellulose from one core had placed this overflow at 8 ka (7200 14C yr B.P.), reevaluation of the age model for this core, in addition to new stratigraphic and chronological evidence from a second core, suggests that basin overflow was established much earlier, ca. 13 ka. Our refined view of the timing of Lake Victoria overflow inferred from the oxygen isotope records is consistent with other paleolimnological studies, indicating that lake-sediment cellulose is an effective and sensitive isotopic archive of major hydrologic events in this region. VL - 30 IS - 6 N1 - id: 1011 JO - Oxygen isotope stratigraphy of sediment cellulose from two cores, Lake Victoria, East Africa ER - TY - JOUR T1 - Holocene lake sediment records of Arctic hydrology JF - Journal of Paleolimnology Y1 - 2000 A1 - MacDonald, G. M. A1 - Felzer, B. A1 - Finney, B. P. A1 - Forman, S. L. KW - Arctic KW - Climate change KW - Holocene KW - paleohydrology KW - paleolimnology AB - Although paleoclimatic research in the Arctic has most often focused on variations in temperature, the Arctic has also experienced changes in hydrologic balance. Changes in Arctic precipitation and evaporation rates affects soils, permafrost, lakes, wetlands, rivers, ice and vegetation. Changes in Arctic soils, permafrost, runoff, and vegetation can influence global climate by changing atmospheric methane and carbon dioxide concentrations, thermohaline circulation, and high latitude albedo. Documenting past variations in Arctic hydrological conditions is important for understanding Arctic climate and the potential response and role of the Arctic in regards to future climate change. Methods for reconstructing past changes in Arctic hydrology from the stratigraphic, isotopic, geochemical and fossil records of lake sediments are being developed, refined and applied in a number of regions. These records suggest that hydrological variations in the Arctic have been regionally asynchronous, reflecting the impacts of different forcing factors including orbitally controlled insolation changes, changes in geography related to coastal emergence, ocean currents, sea ice extent, and atmospheric circulation. Despite considerable progress, much work remains to be done on the development of paleohydrological proxies and their application to the Arctic. VL - 24 IS - 1 N1 - id: 375 JO - S. L. Holocene lake sediment records of Arctic hydrology ER -