中国大陆主要块体现今变形状态的反演研究

本文利用中国大陆的GPS运动速度场,研究了其中的7个亚板块和14个构造块体的变形状态,并做了动力学解释。研究中,构造了一种运动-变形模型来提取观测数据中的变形信息。结果表明:南北构造带东西两侧应变状态表现出显著的差异,西部各亚板块或块体的主应变量值从约4.5×10-8.a-1到约1.3×10-8.a-1,东部则从约3.0×10-.8a-1到约0.4×10-.8a-1,表明东西两部应变量值有较大的落差,并且主压应变方向从西部的北北东向逐步转到东部北东东向。南北构造带表现为其不同段落的各块体的变形趋势和量级都有显著不同。川滇块体是东部与西部的结合部位,变形量较大,主压应变为3.4×10-8.a-1,反映了印度板块向北的推挤在川滇块体造成了较大变形。中国北部地区向东西两个方向运动,塔里木块体、准噶尔块体、天山块体向西,柴达木-祁连山块体、阿拉善块体向东。这种推挤力和太平洋板块阻碍、遏制作用,造成了华北块体、鄂尔多斯块体以拉张为主的应变和逆时针旋转。

Inversion study on present-day deformation state of the main blocks in Chinese continent

Using GPS velocity field,we have studied present-day deformation state of 7 sub-plates and 14 principal tectonic plates in Chinese continent,and its geodynamic meaning is explained.In this study,the deformation information of the plates is distilled from observations using model of movement and deformation,and this model has been given in this paper.The results reveal that prominent difference of deformation state is presented in east and west side of the south and north tectonic zone, the main strain rate of the plates in the west is about from.a~(-1) to .a~(-1),and is about from.a~(-1) to.a~(-1) in the east.This results reveal that the east and west sides in Chinese continent has a big difference in deformation rate,and the direction of principal deformation rate has changed from NNE direction in the west to NEE direction in the east gradually.The trend and grade of deformation in the plates of difference paragraph has a prominent difference in the south and north tectonic zone.Chuan-dian block is combinative part of east and west,the deformation is bigger,and the main press strain rate is about.a~(-1),which reflects the extrusion in north direction of Indian block toward north formed the great deformation in Chuan-dian block.In north area,Chinese continent has a motion in east and west direction,Tarim,Zunger and Tianshan block west,Chaidamu- Qilian and Alashan block east.The north China and Ordos block have the dilatation strain mainly and anti-clockwise rotation for the effect of extrusion and counteraction in the Pacific Ocean block..