Timing and style of Late Pleistocene glaciation in the Queer Shan,northern Hengduan Mountains in the eastern Tibetan Plateau

Glacial landforms and sediments provide evidence for the existence of two Late Pleistocene major glacial advances in the Queer Shan, northern Hengduan Mountains in the eastern Tibetan Plateau. In the current study, optically stimulated luminescence and electron spin resonance dating results reveal that the two glacial advances occurred during Marine Isotope Stage (MIS) 3 and the Last Glacial Maximum (LGM) in MIS 2, respectively. Geomorphic evidence shows that the glacial advance during MIS 3 was more extensive than that in MIS 2. This glacial advance is synchronous with other glaciated areas in the Himalaya and Tibet, but contrasts with global ice volumes that reached their maximum extent during the LGM. Glaciers in the Queer Shan are of the summer accumulation type and are mainly fed by precipitation from the south Asian monsoon. Palaeoclimate proxies show that during MIS 3 the south Asian monsoon strengthened and extended further north into the Tibetan Plateau to supply more precipitation as snow at high altitudes. This in turn led to positive glacier mass balances and caused glaciers to advance. However, during the LGM, despite cooler temperature than in MIS 3, the weakened south Asian monsoon and the associated reduced precipitation were not as favourable for glacier expansion as in MIS 3. Copyright © 2010 John Wiley & Sons, Ltd.     

Geomorphic and chronometric evidence for high lake level history in Gahai Lake and Toson Lake of north‐eastern Qaidam Basin,north‐eastern Qinghai–Tibetan Plateau

Palaeoshorelines, highstand lacustrine sediments and lakeshore terraces are preserved around saline lakes in the arid Qaidam Basin. Previous research indicates that the chronology of a mega‐paleolake in the Qaidam Basin during the late Pleisotocene is controversial. Here we report quartz optically stimulated luminescence (OSL) age estimates of highstand lacustrine sediments, shoreline features and geomorphic exposures that contribute to a revision of the lake level history of Gahai and Toson lakes in the north‐eastern Qaidam Basin, on the northeastern Qinghai–Tibetan Plateau (QTP) margin. The results imply that: (i) high lake levels at Gahai and Toson lakes based on quartz OSL dating occurred at 85–72, 63–55, 31, 5.4 and 0.9–0.7 ka, probably corresponding to periods of warm and wet climate; (ii) periods of high lake levels are almost synchronous with other lakes on the QTP (e.g. Qinghai and Namco lakes), with the highest late Pleistocene levels occurring during Marine Oxygen Isotope Stage 5; and (iii) highstand phases on the QTP are out of phase with those of low‐latitude lakes in the southern hemisphere, possibly driven by solar insolation variability in the low‐latitude region. Copyright © 2012 John Wiley & Sons, Ltd.