关键词: 玛纳斯湖, 准噶尔盆地, 游移湖, 湖泊演化, 入湖水量, 新疆

Abstract: Thanks to global climate change and human activities, lakes have changed dramatically in the Junggar Basin of Xinjiang in recent 50 years. Based on the remote sensing images from Beijing satellite No.1 in 2006 together with the measured topographical data in 1999 and other data since the 1950s, this paper analyzes mainly the features of landforms around the Manas Lake and the change of feeding sources of the lake. The results are as follows: (1) Tectonic movement brought about the fundamental geomorphologic basis for lacustrine evolution; the Manas Lake is one of the small lakes broken up from the Old Manas Lake due to tectonic movement and drought climate; the Manas Lake had existed before the Manas River flowed into it in 1915. The geomorphologic evidences for evolution of the Manas Lake include: (a) Diluvial fans and old channels at the north of the lake indicate that the rivers rising in the mountains north of the Junggar Basin had fed the Old Manas Lake and now still feed the lake as seasonal rivers; (b) The wandering lakes, old channels, alluvial fan, etc. indicate that the Old Manas Lake was fed by many rivers rising in the mountains except by the Manas River; (c) The elevations of the alluvial and diluvial fans are all within the extent of 280 m a. s. l., which may prove that the elevation of the Old Manas Lake was about 280 m a. s. l.; (d) Core analysis for the Manas Lake area also indicates that the Manas Lake has existed since Late Pleistocene epoch; (2) Analysis on the feeding relations between the lakes and the lacustrine evolution shows that human activities are one of the main driving forces of lacustrine evolution in recent 50 years, and it is the precondition of restoring and maintaining the lacustrine wetlands in the study area to satisfy the feeding of the Baiyang and Manas rivers and the inflow of the Manas Lake.

Key words: Manas Lake, Junggar Basin, wandering lake, lacustrine evolution, lake inflow, Xinjiang