Acta Geographica Sinica ›› 2018, Vol. 73 ›› Issue (5): 957-972.doi: 10.11821/dlxb201805014

• Earth Surface Process • Previous Articles     Next Articles

Optically stimulated luminescence dating of moraines in East Altay Mountains, Xinjiang

JIA Binbin1(),ZHOU Yali1(),ZHAO Jun2   

  1. 1. School of Geography and Tourism, Shaanxi Normal University, Xi'an 710062, China
    2. No.8 Gold Geological Party, CPAPF, Xinjiang, Urumqi 830057, China
  • Received:2017-06-26 Online:2018-05-03 Published:2018-05-03
  • Supported by:
    National Natural Science Foundation of China, No.41371029;China Postdoctoral Science Foundation, No.2012T50795;China Postdoctoral Fund Project, No.2011M501443

Abstract:

The glacier is one of the most positive external forces for shaping the landscape of earth surface in alpine region. The geochronology study of glacial stratigraphy can provide insightful information about the ancient glacier process, which is sensitive to climate change. Compared to the sediments of ice lake and ice water terrace with complex material source, moraine is the direct product of glacial movement. Consequently, it can also reflect the glacier events that occurred in the past. The accurate dating of moraine can provide chronology evidence for improving the understanding of reconstruction of climate change patterns. The Altay Mountains is one of the major mountain ranges for understanding Quaternary glaciation in northwestern China. Most of the studies have focused on western Altay Mountains, Xinjiang. However, the chronology of the moraines in its eastern section is not well studied. In this study, OSL dating technique method was applied to determine the ages of the glacial moraine deposits of coarse grained quartz (90-125 μm) in the East Altay Mountains. According to analysis of the frequency distribution of De value and De(t) plots, most of the moraine samples showed partial bleaching. Therefore, the first-order kinetic equation was used to separate the CW-OSL curve into three component exponentials (fast, medium and slow components) and the fast components were used to determine these equivalent doses. The OSL dating results of moraines in East Altay Mountains deposited seperately in 32.33 ka, 16.07 ka, 8.41-8.07 ka, 6.83-6.48 ka and 4.62 ka. This implied that the glacier development process was identified with MIS3, MIS2, 8.2 ka Cold Events, Holocene Optimum and Neoglaciation, respectively. Observably, moraine can occur with glacial advance or recession during the warm or cold climate episodes, while the development of glaciers in the Altay Mountains was closely related to global climate change. This study demonstrates the successful application of quartz OSL with fast component signal to glacial sediments from the Altay Mountains. Furthermore, it can complement the geochronology data for moraine sedimentary records to reveal the glacier evolution history in the whole Altay Mountains region since 32 ka BP.

Key words: Altay Mountains, moraines, OSL dating, glacial movement