Fluctuation in the Level of Pluvial Lake Lahontan During the Last 40,000 Years
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/223480686 Fluctuation in the level of pluvial Lake Lahontan during the last 40,000 years Article in Quaternary Research · May 1978 DOI: 10.1016/0033-5894(78)90035-2 CITATIONS READS 91 132 All content following this page was uploaded by Larry V. Benson on 29 May 2014. The user has requested enhancement of the downloaded file. QUATERNARY RESEARCH 9,300-318 (1978) Fluctuation in the Level of Pluvial Lake Lahontan During the Last 40,000 Years LARRY V. BENSON Earth Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California Received July 25, 1977 Samples of algal tufa, gastropods and calcite-cemented-<and were collected from the Walker and Pyramid Lake areas of the Lahontan Basin, Nevada.; X-ray diffraction petrographic and radiocarbon analyses show that massive forms o i %& such as the dendritic variety contain secondary carbon-bearing material and therefore yield unreliable radiocarbon dates. Dense coating of tufa (lithoid), however, gave radiocarbon ages in agreement with dates on coexisting aragonite gastropods. Radiocarbon data from the study were combined with previously dated noncarbonate materials [Born, S. M. (1972). “Lake Quatemary History, Deltaic Sedimentation, and Mudlump Formation at Pyramid Lake, Nevada,” Center for Water Resources, Desert Research Inst., Reno, Nevada] to give an internally consistent record of lake level fluctuations for the past 40,000 years. The main features of the Lahontan chronology are (1) extreme high stands (1330 m above sea level) 13,500 to 11,000 and 25,000 to 22,000 B.P., (2) a moderate high stand (1260 m above sea level) 20,000 to 15,000 B.P., (3) a low stand of unknown elevation 40,000 to 25,000 B.P., (4) an extremely low stand 9000 to 5OOO.EP?.and (5) an overall increas;;‘Ei%e%e~%&r and Pyramid Lakes du%g-the past 5000 years, until the late 19th century.
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