摘要
本文根据369个大中型纵弯褶皱与157个节理观测点的资料,对中国白垩纪—早始新世的构造应力场进行了恢复、发现中国东部最大主压应力轴的产状为NE32°—SW212°,近于水平;而在西部,则为NE15°—SW195°,也近于水平。另外根据褶皱翼角与古构造应力值的估算表明,该时期的构造作用由中国的西南部向东北有逐渐减弱的趋势。在2—3km深处,其西藏的差应力达183MPa;而在华北、华东为100MPa左右。笔者认为白垩纪—始新世早期的构造应力是与该时期的印度-澳大利亚板块朝北北东方向运移和推挤作用有关。
On the basis of the data of 369 large- and middle-scale flexural folds and 157 joint sets, the directions of the tectonic stress field of the Cretaceous-early Eocene in China are reconstructed. In eastern China, the maximum principal compressive stress axes are mainly oriented in NE32°—SW212。 direction, nearly horizontal; the axes of the intermediate stresses (i.e. fold axes) mainly Strike NW302°—SE122° and dip at a low angle; the axes of the minimum principal compressive stresses are almost vertical; in western China, the directions of the maximum principal compressive stresses are NE15°—SW195° and characterized by a low dip angle; the intermediate stress axes strike NW285°—SE105° and dip at a low angle, and the minimum principal compressive stress axes are also nearly vertical.From the estimation of the dip angles of fold limbs and the paleotectonic stress values, the tectonic stresses of this period were strong in the southwest and weak in the northeast. At a depth of 2—3 km, the differential stress value can change from 183 MPa in Xizang (Tibet) to about 100 MPa in North China and East China.According to the analysis of palaeomagnetic data, it is considered that the Cretaceous-early Eocene tectonic stress field in China is related to the motion and pushing of the Indian-Australian plate in a north-by-east direction.Considering that the Cretaceous-early Eocene tectonic stress field and their formation inechanism are distinctly different from those of the Jurassic, it is not advisable to call the Cretaceous-early Eocene tectonic movement the late Yanshanian tectonic movement. The authors suggest that the term 'Sichuan movement' should be restored. The period from the Jurassic to early Paleogene may be collectively called the 'Pacific tectonic stage'.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1989年第1期14-25,共12页
Acta Geologica Sinica
