昆仑山区青藏公路沿线冰缘现象

PERIGLACIAL PHENOMENA ALONG QINGHAI XIZANG HIGHWAY IN THE KUNLUN MOUNTAINOUS REGION

本区位于东昆仑山腹地,青藏高原多年冻土区的北缘。区内海拔高,地形相对高差较大,气候寒冷而较干旱。故冰缘作用强烈,冰缘现象种类繁多。本区冰缘作用及其形态类型的分布具明显的垂直地带性。自高至低有4个冰缘作用带,各带内冰缘现象不同。区内冰缘现象的动态变化相当复杂,这与环境条件有关,主要决定于自身的生成条件。

The investigated region is looted in the centre of the Kunlun Mountainous Region. Mountains are distributed in the northern and southern parts of the region, at 5000-6000m and 4500-5500m a. s. 1. respectively. The central part is fault valley, at 4100-4500m a. s. 1. and higher in western part than in eastern part. The mountain range and fault valley run from east to west. The cold and semi-arid climate results in intensive periglacial processes and various kinds of periglacial phenomenon.The periglacial actions and geomorphological forms in this region show obviously vertical zonality. From upper part to lower part, the periglacial action zones can be divided into the following:1.Frost weathering-nivation zone: above 4700m or 4800m a. s. 1. , including nivation cirques, block field, rock pillars and rock pinnacles.2.Frost sorting gravitati zone: at 4800-4200m a. s. 1. , including debris flows, rock rivers, stone-stripes, rock glaciers and rock-circles.3.Frost heave-thaw settlement zone: at 4800-4200m a. s. 1. , including thaw-slumping, gelifluction. pingus and polygons.4.Wind erosion and seasonal frost zone : below 4200m a. s. 1. , dominated by dunes. Dynamic variations of the periglacial phenomena are very complicated, related to the environmental factors, especially to the partial properties of themselves (such as temperature, moi sture and material conditions etc. ).