鄂尔多斯的逆时针旋转与动力学

COUNTERCLOCKWISE ROTATION AND GEODYNAMICS OF ORDOS BLOCK

根据鄂尔多斯块体及周围地区的GPS数据,计算了鄂尔多斯相对于蒙古地台和欧亚板块的旋转参数,表明鄂尔多斯相对于蒙古地台和欧亚板块存在逆时针旋转。用GPS方法与地质学方法得到的鄂尔多斯相对于蒙古地台的旋转参数相同,证明鄂尔多斯自晚新生代以来的运动是稳定的。分析周围地区相对于鄂尔多斯的运动以及鄂尔多斯周围边界断裂带两侧的相对运动,发现鄂尔多斯主要受两对力作用:鄂尔多斯北部北西向拉张与南部北东向推挤形成的力矩作用,以及燕山块体对鄂尔多斯的NW向拉张作用力与华南块体对鄂尔多斯SE向拉张作用力。这两对作用力是促使鄂尔多斯发生逆时针旋转的驱动力。

On the basis of the GPS data observed on Ordos block and its peripheral regions, the rotation parameters of Ordos block relative to Mongolia platform and Eurasia plate are calculated, which prove the counterclockwise rotation of Ordos block relative to Mongolia platform and Eurasia plate. The rotation parameters of Ordos block relative to Mongolia platform obtained by GPS method are the same as those acquired by geological method, which indicate that the motion of Ordos block has been stable since late Kainozoic. We have discovered from the motion in the peripheral regions of Ordos block relative to the block itself and the relative motion between the boundary fault zones around Ordos block that Ordos block is mainly subject to two pairs of forces： （1） the moment of force formed by the NW-trending tension to the northern Ordos and the NE-trending pushing to the southern Ordos; （2） NW-trending tension of Ordos by Yanshan block and SE-trending tension of Ordos by South China block. These are the two driving forces for the counterclockwise rotation of Ordos block.