PROGRESS IN GEOGRAPHY ›› 2013, Vol. 32 ›› Issue (2): 262-269.doi: 10.11820/dlkxjz.2013.02.012

• Original Articles • Previous Articles     Next Articles

OSL dating study on the glacial evolutions during the Last Glaciation at Dangzi Valley in the eastern Qinghai-Tibetan Plateau

OU Xianjiao1,2, ZHANG Biao3, LAI Zhongping2, ZHOU Shangzhe4, ZENG Lanhua1   

  1. 1. School of Geography and Tourism, Jiaying University, Meizhou 514015, China;
    2. State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000, China;
    3. The North-east Party of Jiangxi Geo-mineral Bureau, Shangrao 334000, China;
    4. School of Geography, South China Normal University, Guangzhou 510631, China
  • Received:2012-07-01 Revised:2012-09-01 Online:2013-02-25 Published:2013-02-07

Abstract: There are four sets of preserved moraines in Dangzi Valley, located in the southeastern edge of Zhuqing Basin, northern slope of Queershan Mountains, the north branch of the Shaluli Mountains in the Hengduan Mountains, eastern part of Qinghai-Tibetan Plateau. Each set of moraines is composed of several small moraines. These are the perfect geomorphological evidence for multiple glacial fluctuations during the Last Glaciation in this region. To reconstruct the history of glacial evolution during the Last Glaciation, seven optically stimulated luminescence(OSL) samples are collected from these moraines. Equivalent doses(De) are determined using SAR(single aliquot regenerative-dose) and SGC(standardized growth curve) protocols. Internal testing results indicate that these protocols are suitable for De determination. The age results show that the first, second, and third sets of moraines were formed during 22.4-16.5 ka BP, belonging to the Marine Isotope Stage 2 (MIS-2), approximately equal to the Last Glacial Maximum (LGM). The fourth set was formed during the MIS-3. These results are in good agreement with the chronology of other sites in the Shaluli Mountains. MIS-3 glacier in this region is bigger than MIS-2 glacier. The existence of nine small moraines in first, second, and third sets indicates that Dangzi Glacier had experienced nine small fluctuations during the period of 22.4-16.5 ka BP. The glacier reached its largest MIS-2 scale a little earlier than 22.4 ka BP. After that, the Dangzi Glacier fluctuated and shrank with time, which is probably the response of the glacier to the increasing solar radiation and the rising temperature during late MIS-2. The most inner moraine was formed at 16.5 ka BP, which may be a sign of onset of local deglaciation. Then, the Dangzi Glacier retreated dramatically and rapidly. Melting water converged into the lower part of the valley and was blocked by the most inner moraine and thus formed the Dangzi Lake.

Key words: Dangzi Valley, Eastern Qinghai- Tibetan Plateau, glacial evolution, OSL dating, Shaluli Mountains, the Last Glaciation