Late-Holocene hydroclimate inferences for the northern Great Basin from Little Lake, Elko County, Nevada, USA

Abstract

Prominent lunette dunes 500–800 m long, 50–80 m wide, and up to 5 m tall are present on the floor of the Independence Valley in northeast Nevada, USA. These dunes border the downwind margins of circular playas at the end of a drainage descending from the East Humboldt Mountains, which terminates in an ephemeral water body named Little Lake. Gastropod shells from the Little Lake playa yield radiocarbon ages of ∼400 cal yr BP, after correction for a hard-water effect. A similar age was obtained for shells from the crest of one of the lunettes. Deeper sediment in this lunette yielded shell ages clustering around 600 cal yr BP. This pattern suggests two intervals of relatively persistent water at Little Lake, both of which ended with lake desiccation and deflation of sediment and shells to the adjacent lunette. Shells from the crest of another lunette yielded radiocarbon ages between 3800 and 1750 cal yr BP. This dune, therefore, is considerably older and accumulated over a much longer stretch of time. Using the Global Surface Water Explorer, years between 1984 and 2018 were identified in which Little Lake contained water in most of the available summer imagery. These years form three clusters: 1984–1987, 1997–2000, and 2017–2018. Snow water equivalent (SWE) is greater in the mountains, snow makes up a greater percent of total annual precipitation, and Palmer Drought Severity Index is more positive in this region, in years when water is present in Little Lake compared with those in which the lake remains dry. Values of the PDO are also higher in years when Little Lake holds water. Although the hydrology of Little Lake may be influenced to an unknown degree by upstream water diversions, this overall pattern implies that the lake and its associated lunettes are a sensitive recorder of late Holocene hydroclimate variability in the northern Great Basin.