The physical record of lakes in the Great Basin

Publisher Website
Google Scholar
Abstract
During the late Pleistocene nearly 100 closed basins in the western United States contained lakes (Fig. 1). Most of these were within the Great Basin area of California, Nevada, Utah, and Oregon; others existed in Arizona, New Mexico, and northern Mexico. Today only a few of these basins contain perennial lakes. This paper addresses the chronology and paleoclimatic history associated with fluctuations of lakes in the Great Basin during the period 25 to 9 ka. Specifically: (1) When did the variations occur? (2) Were the lake-level changes synchronous across the region? (3) What types of paleoclimatic changes were responsible for the changes in lake size? (4) Did the paleoclimatic changes implied by lake-level records have a magnitude similar to that inferred from other proxy data, and did these changes occur at the same time in the different systems? (5) Do extreme climatic and hydrologic events in the historic period offer analogs for prehistoric conditions that created the Pleistocene lake systems? (6) What were the effects of the continental ice sheets on the Pleistocene climate of the Great Basin? Previous investigators (Morrison, 1965; Mifflin and Wheat, 1979; Davis, 1982; Smith and Street-Perrott, 1983; Harrison and Metcalfe, 1985) cataloged lake-level data and presented various interpretations of selected lake-level chronologies. This chapter does not duplicate these works, but instead it focuses on those lake systems that have been intensively studied and that have well-documented absolute-age chronologies. Throughout ensuing sections, calculations and quantitative discussion of processes commonly use Lake Lahontan as an example because of data availability and the authors’ greater experience with this lake system. It should be kept in mind that differences in bathymetry and other details of the local setting cause each lake system to respond to climatic change in a somewhat unique manner.