Acta Geographica Sinica ›› 2011, Vol. 66 ›› Issue (11): 1540-1550.doi: 10.11821/xb201111010

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Fluvial Incision Process and Its Tectonic Implications of Golmud River since Last Glaciation Maximum

CHEN Yixin1, ZHANG Mei1, LI Chuanchuan1, LI Yingkui2, LIU Gengnian1   

  1. 1. College of Urban and Environmental Sciences, Peking University, Beijing 100871, China;
    2. Department of Geography, University of Tennessee, Knoxville, TN 37996, USA
  • Received:2011-06-20 Revised:2011-08-31 Online:2011-11-20 Published:2011-11-20
  • Supported by:

    National Natural Science Foundation of China, No.40571014; No.40971002; National BasicResearch Program of China (973 Program), No.2005CB422001

Abstract: The Golmud River originates from the Kunlun Mountains and drains into the Qaidam Basin on northern Tibetan Plateau. The Golmud River valley has experienced intensive tectonic movements since the Last Glacial Maximum, which deeply influenced the geomorphologic evolution of the river. In addition, well-developed fluvial terraces and sediments are preserved in the river valley and provide vital information for studying the environmental evolution in detail. Four terraces developed in the river valley since the Last Glacial Maximum, which may be responses to four tectonic uplift events. In Nachitai and Sanchahe sections, the incision rates of the four terraces are 9.33-3.33 mm/a (T4-T3, 16-13 ka BP), 12-5.5 mm/a (T3-T2, 13-11 ka BP), 1.0-0.33 mm/a (T2-T1, 11-5 ka BP) and 0.8-0.6 mm/a (T1, since 5 ka BP), respectively. The incision rate increased from 16-11 ka BP, and then it has been decreasing since 11 ka, which implies the tectonic uplift processes. The average incision rate of Xiaonanchuan since 5 ka BP is 4 mm/a. The rate is larger than that of Sanchahe and Nachitai, indicating that the tectonic uplift is more intensive in this region. The longitudinal section of the terraces indicates that the rates and depths of incision were the largest in Sanchahe section (62 m, 3.88 mm/a) and on the piedmont (46 m, 2.88 mm/a), while it was mild in Nachitai section (26 m, 1.61 mm/a). The deformation of the terraces suggests that the Yeniugou fault at Sanchahe and the Hongshigou fault on the piedmont have been active since the Last Glacial. The Kunlun river fault is a thrust fault, and its uplift rates started to rise at 16-13 ka BP, and peaked during 13-11 ka BP, and decreased after 11 ka BP.

Key words: Golmud River, fluvial terrace, incision rate, tectonic uplift