A Reconstruction of Precipitation and Hydrologic Variability on the Peruvian and Bolivian Altiplano During the Late Quaternary

• Main Author: Nunnery, James Andrew
• Other Authors: Baker, Paul A
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: 2012
• Subjects: Paleoclimate science; Geochemistry; Hydrologic sciences; The Altiplano; North Atlantic
• Online Access: https://hdl.handle.net/10161/5557

The Peruvian/Bolivian Altiplano is an important hydrologic system for paleoclimate reconstruction because it is unique in its ability to record climate variability associated with the near-continental scale South American summer monsoon (SASM), which is responsible for much of the precipitation over the Amazon basin and the southern subtropics. Over long timescales moisture on the Altiplano fluctuates in intensity due to changes in precessional insolation forcing as well as teleconnections to decadal-to-millennial scale abrupt temperature shifts in the Northern hemisphere Atlantic. These long-term changes in moisture transport to the Altiplano have been observed in multiple paleoclimate records, including drill core records and paleo-lake level records, as apparent advances and retreats of large lakes in the terminal basin occupied by the Salar de Uyuni and the Salar de Coipasa. Presented here are the results from three studies that utilize different methods to create a refined reconstruction of paleohydrology, as well as paleoclimate, on the Altiplano. A major goal of this research is a more detailed understanding of millennial scale climate variability as it relates to insolation changes and abrupt warming and cooling in the north Atlantic. The first study discusses the creation of a paleohydrologic profile to reconstruct north-south hydrological history using previously reported lake core sediment records the northern and southern basins of the Altiplano, and a new 14 m core from the Salar de Coipasa representing the last ~45 ka. The second study uses a terrestrial hydrology model to simulate lake level changes through time given changes in precipitation and temperature. The third study uses strontium isotopic measurements of carbonates and halites in a 220-m core from the Salar de Uyuni to determine how source waters to the southern basin have changed through time. The paleohydrologic profile in the first study is constructed using records from three major basins within the Altiplano: Lake Titicaca in the ...