四川盆地中新生代未发生旋转的古地磁证据

四川盆地中生代以来沉积中心经历弧形迁移,盆地是否发生旋转具有争议。根据古地磁数据计算古纬度表明,四川盆地晚二叠世以来主要经历了大规模北向漂移、南向漂移、快速北向漂移过程。以现有精度古地磁数据分析表明,四川盆地中生代以来,其相对于欧亚大陆、扬子地块旋转量都小于数据本身的误差值,相对于欧亚大陆和扬子地块都没有有效意义的旋转。综合分析认为,四川盆地中新生代沉积中心的弧形迁移,反映了周缘造山带不同时期的构造活动对四川盆地沉降及沉积的控制。

PALEOMAGNETIC EVIDENCE OF THE NON-ROTATION FOR MESO-CENOZOIC SICHUAN BASIN

Since Mesozoic era,the sedimentary center of Sichuan Basin has undergone arcuate migration,but whether the basin has been rotated is still left in the air.The calculated paleolatitude by the paleomagnetic date shows that since Late Permian Epoch,the basin has undergone the following processes:large-size migration to the north,migration to the south and rapid migration to the north.According to the current precision analysis of the paleomagnetic date,since the Mesozoic era of Sichuan Basin,relative to the Eurasian Continent and Yangtze Block,the rotated amounts are less than the error values of the data themselves,and moreover there are no effectively significant rotations.The comprehensive analysis shows that the arc migrations in the Meso-Cenozoic sedimentary centers response the controls of the structural activities of the marginal orogenic belts in different periods on the settlement and sedimentation of Sichuan Basin.