天山南麓台兰河口丘状堆积物成因及时代的新见解

研究表明台兰河口的丘状堆积体属古泥石流成因，物质组成显示泥石流形成于中低山带的峡谷段，泥石流可能由谷坡堆积物（主要为钙质胶结的冰碛）滑塌阻塞河床发展而成。其形成时代晚于末次冰期，应在全新世中期或更晚一些。

THE ORIGIN AND AGE OF THE HUMMOCKY DEPOSIT OUTSIDE THE MOUTH OF THE TAILAN RIVER ON THE SOUTH OF THE TUMUOR PEAK,TIANSHAN,CHINA

The Hummocky deposit distributes from the north to the south as linear features, and extends along the river valley outside of the mouth of the Tailan River. It is about 2.5 to l5m thick, cuts through the innermost piedmont moraines (of last glacial stage). The deposit settles on a gravel layer of the river terrace, and is covered by recent diluvium at a few p1aces. Its composition can be mainly divided into two parts: (1) bou1ders of the carbonate-cemented tillites from the paleo-till at the valley slopes in the middle and lower mountains region; (2) deposits among the boulders. The later is much more complex in lithologic composition. Besides a large percentage from the paleo-tillites, lots of outwash deposits and fluvial deposits were mixed together. the boulders of tillites are obviously rounded. The largest bou1ders and the hills all become smaller in size along the way from upper to down. Many facts show that the hummocky deposit was formed by a paleo-mud-rock flow. The mud-rock flow was developed from large landsilde and rocky avalanches at the deep dissected valley slopes of the Tailan River in the middle and lower mountains. The big environmental event occurred later than the last glaciation, probably in the middle Holocene.