祁连山-河西走廊地区的现今水平形变

RECENT HORIZONTAL DEFORMATION IN QILIANSHAN-HEXI CORRIDOR AREA

根据祁连山 河西走廊地区的两次GPS测量的结果 ,研究了该地区在整个欧亚板块运动的背景下的内部水平变形。按照刘百篪对该地区的主要构造的最新研究结果 ,GPS观测资料覆盖区可划分为 5个次级块体 (祁连山、阿拉善、塔里木、西宁 兰州、共和次级块体 )。除其中共和块体因仅有一个观测点而无法进行研究之外 ,对其余4个块体用刚体运动加均匀应变模型研究了这些构造块体的相对运动和变形。结果表明 ,这些块体内的应变参数显著性不高 ,即该地区的现今水平变形以区内一些次级块体的整体相对运动为主 ,应变积累只占次要地位。这些次级块体间的边界断裂大多数仍呈现为某种继承性运动 ,只是在本区西北部的祁连山次级块体与塔里木块体交界部位现今运动表现出与继承性运动不同的性质。由于与该边界有关的两侧块体上的观测点仍嫌不足 ,这一结论的可靠性尚待进一步验证。

On the basis of the results obtained in the two periods of GPS campaign in the Qilianshan-Hexi Corridor area, the inner deformation under the background of Eurasian plate motion is studied in this paper. Following the latest study results on the main tectonic in the area made by Prof. Liu Baichi , the area covered by the GPS observational data can be divided into five secondary blocks (Qilianshan, Alashan, Talimu, Xining-Lanzhou and Gonghe blocks). Among the five blocks, only one station is situated in the Gonghe block, it is not possible to do the further study for this block. For four other blocks, the relative block motion and deformation are studied under the model of rigid motion and uniform strain. The results show that the strain parameters of these blocks are of insignificance. In the other words, the recent horizontal deformations are mainly shown as the entirely relative motions between the secondary blocks and the strain accumulations only play less important roles. The most faults in the boundary zones show some inherited motions, except the motion on the boundary fault between the Qilianshan block and the Talimu block in northwest part of the area which shows a different pattern with the inherited one. Unfortunately, the amount of stations on bilateral blocks of the boundary fault is not large enough, reliability of the conclusion is still to be further identified and tested.