Abstract
We applied luminescence dating to a suite of shorelines constructed by pluvial Lake Clover in northeastern Nevada, USA during the last glacial cycle. At its maximum extent, the lake covered 740 km2 with a mean depth of 16 m and a water volume of 13 km3. In the north-central sector of the lake basin, 10 obvious beach ridges extend from the highstand to the lowest shoreline over a horizontal distance of ~1.5 km, representing a lake area decrease of 35%. These ridges are primarily composed of sandy gravel and rise ~1.0 m above the alluvial fan surface on which they are superposed. Single grain luminescence dating of K-feldspar using the pIRIR SAR (post-infrared infrared single-aliquot regenerative dose) protocol, corroborated by SAR dating of quartz, indicates that the highstand shoreline was constructed ca. 16–17 ka during Heinrich Stadial I (Greenland Stadial 2, GS-2), matching 14C age control for this shoreline elsewhere in the basin. The lake regressed rapidly during the Bølling/Allerød (GI-1), before the rate of regression slowed during the Younger Dryas interval (GS-1). The lowest shoreline was constructed ca. 10 ka. Persistence of Lake Clover into the early Holocene may reflect enhanced monsoonal precipitation driven by the summer insolation maximum.
Highlights
The pluvial lakes that existed in and around the Great Basin at times during the Pleistocene are the most iconic evidence for the profound hydroclimate shifts that accompanied glacial-deglacial cycles in southwestern North America
This study developed a top-to-bottom chronology for the entire suite of shorelines constructed by a former pluvial lake
Topographic surveying with the total station, combined with the vertical adjustment detailed in Figure 4, indicates that shorelines were built when Lake Clover stood at elevations of 1725, 1724, 1723, 1721, 1720, 1718, 1717, 1715, 1713, and 1712 m (Figure 5)
Summary
The rather remarkable realization that this dry landscape was once much wetter has motivated more than a century of research into the former size and distribution of these pluvial lakes [3,4], and considerable work over the past several decades has applied a variety of absolute dating methods to determine when these lakes reached their maximum dimensions [5,6]. These efforts have led to comprehensive catalogs of pluvial lake distribution [7], and sometimes conflicting theories about the climatic controls on these lake highstands [8,9,10,11,12].
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