Last deglacial and Holocene lake level variations of Qinghai Lake, north-eastern Qinghai-Tibetan Plateau

Abstract

Qinghai Lake is of significance for paleoclimate research because it lies in a pivotal region that is influenced by both the mid‐latitude Westerlies and the low‐latitude Asian summer monsoon (ASM). Most published lake level histories of Qinghai Lake are interpreted from drill‐core proxies. Here we combine geomorphic shoreline investigations with optically stimulated luminescence dating to constrain lake level variations since the last deglacial. The results indicate that two periods of highstands occurred during the last deglacial (∼16–14.9 and ∼12.6–12.2 ka), and that lake levels were 6–7.4 m higher than at present. Lake levels dropped abruptly during the Younger Dryas, and were generally low with frequent fluctuations during the early Holocene. Qinghai Lake reached its highest Holocene level, 9.1 m higher than modern, at ∼5 ka, and has regressed during the past 2 ka. We propose that high lake levels during the last deglacial were due mainly to melting glacial and permafrost waters, supplemented by enhanced Westerlies precipitation and decreased evaporation during Heinrich Event 1 (∼16–14.9 ka) and increased ASM rainfall during the Bølling–Alleröd warm period (∼14–12 ka). Lake level fluctuations during the Holocene were generally in accordance with moisture variations in the marginal monsoon zones of inland China.

Lake Water Depth Controlling Archaeal Tetraether Distributions in Midlatitude Asia: Implications for Paleo Lake‐Level Reconstruction

“…However, based on the relatively high %OH‐GDGTs which is less likely influenced by soil input as soil group 1.1b Thaumarchaeota produce crenarchaeol but not OH‐GDGTs, we can confirm that Lake Qinghai was relatively deep during deglaciation, at least intermittently (Figure e). The deglacial intermittent high stand reconstructed by %cren and %OH‐GDGTs is in general agreement with the discontinuous lake‐level record inferred from paleoshoreline deposits (Figure f; Liu et al, ) and is possibly due to high meltwater input or low evaporation loss.…”

“…Comparing past variations in %cren and %OH‐GDGTs with reconstructed paleohydrological history of Lake Qinghai since the last deglaciation. (a) δ 18 O of ostracod shells, used as a proxy for effective precipitation (Liu et al, ); (b) δ 13 C of total organic carbon, with more negative values indicating higher lake level (Liu, Li, et al, ); (c) Water level variations based on ostracod Sr/Ca‐inferred salinity changes (Zhang et al, ); (d) Sketched lake‐level history based on multievidence (Yu, ); (e) %cren (sky blue line; Wang et al, ) and %OH‐GDGTs (orange; 0‐ to 8‐ka data from Wang, Liu, et al ()); (f) Sketched shoreline history for Lake Qinghai, with shoreline elevations plotted against age estimates (Liu et al, ); (g) Thaumarchaeol amoA gene abundance (Yang et al, ).…”

“…Our understanding of past hydroclimate reconstructed by lake‐level fluctuations cannot only offer valuable insight into the underlying forcing mechanisms for hydrological variability but also help to project future hydrological trends (Chen et al, ; Hanrahan et al, ; Shuman et al, ; Street & Grove, ). Generally, variations in paleo lake levels can be reconstructed by physical approaches such as remnant geomorphologic features above present lake levels (Liu et al, ) and littoral sedimentary facies (Newby et al, ), biotic indices such as ostracod assemblages (Mischke et al, ), chironomids (Chen et al, ), and submerged plant residues (Yu, ), and geochemical indices such as carbonate content (Zhao et al, ), total organic carbon isotopes (Liu et al, ), and n ‐alkanes and alkenones (He et al, ). However, each technique has inherent strengths and weaknesses (Juggins, ; Lister et al, ; Liu et al, ) and few lake‐level indices have been reported to be universally valid.…”

Linkage of Climatic Factors and Human Activities with Water Level Fluctuations in Qinghai Lake in the Northeastern Tibetan Plateau, China

“…As the largest inland lake in China, the variation in the water level of Qinghai Lake has attracted a great deal of attention [30,31]. In our study, the lake water level was shown to have declined from 1959 to 2000, which was consistent with Li [32], who came to the same conclusion that the lake water level had tended to decrease in the years from 1959 to 2000.…”

Quantitative precipitation estimates for the northeastern Qinghai‐Tibetan Plateau over the last 18,000 years

“…During the Late Glacial period, PANN was particularly variable between ~18,000 and ~15,000 cal years B.P., yet consistent with a high lake water‐level reconstructed from paleoshorelines for our study area [e.g., X. J. Liu et al , ; Chen et al , ] and a high annual rainfall amount inferred from 10 Be records for the nearby Chinese Loess Plateau (CLP) [ Zhou et al , ], with westerlies commonly suggested as the dominant driver of paleoclimatic change at this time interval in western and northern China [e.g., An et al , ; Komatsu and Tsukamoto , ; Thomas et al , ]. The plausible explanation might be related to enhanced moisture contents carried by westerlies during the late Pleistocene period with expanded areas of Caspian and Black Seas and increased amounts of melting ice sheets, glaciers, and permafrost in the Eurasian continent, due largely to rapid intensification of total summertime solar insolation in the middle‐ and high‐latitude regions of the Northern Hemisphere [e.g., Clark and Mccabe , ; Badertscher et al , ; Dortch et al , ; X. J. Liu et al , ] (Figure ). The period from ~15,000 to ~13,000 cal years B.P.…”