天山乌鲁木齐河源空冰斗中分选环的观测与研究

OBSERVATION AND RESEARCH OF SORTED CIRCLES IN EMPTY CIRQUE AT THE HEAD OF URUMQI RIVER,TIAN SHAN, CHINA

本文研究了天山乌鲁木齐河源空冰斗中不同发育阶段的分选环的特征和同一发育阶段分选环的差异。对各阶段的分选环进行了形态、粒度、含水量、冻胀情况、砾石分选、组构以及用木桩垂直打入地下的观测和分析。

Field investigations have been carried out in the.empty cirque a the head of Urumqi River, Tian Shan,for the 1988-1991 period ,in order to study features of sorted circles in different developmental stages and diversith of sorted circles in the same developemental stage. The features of the sorted circles have been analysed with the form of the sorted in the same devlopmental stage. The features of the sorted circle,grain size, water content,frost heave stone sorting,fabric and reference to wooden stakes inserted vertically into the ground. The results show that the sorting degree becomes much better; the influenced of frostheave decreases gradually; and the centre of sorted circles was covered by vegetation increasingly from the upper to lower sorted circles (from infant stage to old stage). Moreover, the general tendency of the frostheave is central frostheave > internal gutter frostheave > gutter frostheave in a sorted circle. The infant sorted circles developed near the material source region and the mature sorted circles were formed far from the source region in the same place.