Quaternary Research Copyright © University of Washington. Published by Cambridge University Press, 2019. doi:10.1017/qua.2018.151 Late Holocene paleohydrology of Walker Lake and the Carson Sink in the western Great Basin, Nevada, USA Kenneth D. Adamsa*, Edward J. Rhodesb aDivision of Earth and Ecosystem Sciences, Desert Research Institute, 2215 Raggio Parkway, Reno, Nevada 89512, USA bDepartment of Geography, University of Sheffield, Sheffield, S10 2TN, United Kingdom *Corresponding author e-mail address:
[email protected] (RECEIVED June 8, 2018; ACCEPTED December 6, 2018) Abstract The late Holocene histories of Walker Lake and the Carson Sink were reconstructed by synthesizing existing data in both basins along with new age constraints from key sites, supplemented with paleohydrologic modeling. The repeated diversions of the Walker River to the Carson Sink and then back to Walker Lake caused Walker Lake–level fluctuations spanning ± 50 m. Low lake levels at about 1000, 750, and 300 cal yr BP are time correlative to the ages of fluvial deposits along the Walker River paleochannel, when flow was directed toward the Carson Sink. The timing and duration of large lakes in the Carson Sink were further refined using moisture-sensitive tree-ring chronologies. The largest lakes required a fourfold to fivefold increase in discharge spanning decades. Addition of Walker River flow to the Carson Sink by itself is inadequate to account for the required discharge. Instead, increases in the runoff coefficient and larger areas of the drainage basin contributing surface runoff may explain the enhanced discharge required to create these large lakes. Keywords: Carson Sink; Holocene; Lake Lahontan; Paleohydrologic modeling; Walker Lake INTRODUCTION of the Walker River, which periodically switched course from one terminal basin to the other (Russell, 1885; Benson and Paleohydrologic records from Great Basin pluvial lakes pro- Thompson, 1987a, 1987b; Benson et al., 1991; King, 1993, vide a rich source of information enhancing understanding of 1996; Adams, 2003, 2007).