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Abstract High-resolution analysis of a 3.80 m sediment core recovered from Deoria Tal, a mid-elevation lake located at 2393 m a.s.l. in the Garhwal Himalaya, documents long-term and abrupt hydroclimate fluctuations in northern India during the mid- to late Holocene. The sediment chronology, based on ten 14 C dates, indicates the core spans 5200 years. Non-destructive, radiological imaging approaches (X-ray fluorescence (XRF), X-ray imaging, and CT scans) were used to assess the response of the lake system to changing hydroclimatic conditions. Variations in elemental concentrations and sediment density evidenced notable hydroclimate change episodes centered at 4850, 4200, and 3100 cal yr BP. Elevated detrital input, greater sediment density, decreased lake ventilation, and lower autochthonous productivity reflects lake deepening between 4350 and 4200 cal yr BP. An abrupt shift in elemental concentrations and sediment density indicated the onset of lake drawdown at 4200 cal yr BP and a negative hydroclimate anomaly between 4200 and 4050 cal yr BP. Lower detrital flux, decreased sediment density, increased oxygenation, and higher autochthonous productivity, reflects a reduction in lake volume between 3200 and 3100 cal yr BP. The potential link between abrupt climate change at 4200 cal yr BP and the contraction of the Indus civilization is explored.
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Late-Holocene hydroclimate inferences for the northern Great Basin from Little Lake, Elko County, Nevada, USA
Prominent lunette dunes 500e800 m long, 50e80 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: 1984e1987, 1997e2000, and 2017e2018. 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.
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- Award ID(s):
- 1702975
- PAR ID:
- 10199003
- Date Published:
- Journal Name:
- Quaternary science reviews
- Volume:
- 244
- ISSN:
- 0277-3791
- Page Range / eLocation ID:
- 106497
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1016/j.quascirev.2020.106497
