THE LATITUDINAL NAPPE STRUCTURE IN THE SUNITEZUOQI OF INNER MONGOLIA

Along the line connecting Tuhamohalagan and Jiaoqier, in the central left Sunite Banner of the Inner Mongolia Autonomous Region, the authors have found a latitudinal nappe zone extending for some 60km. Within the belt,the mid-late Proterozoic(epimetamorphic) green-schists were ovethrust from south to north onto the late Paleozoic granitic batholith at a low angle. On the hanging wall of the nappe (thrust),isoclinal folds are developed with the axial planes inclined to the north in association with imbricated thrusts dipping to the south. In the foot wall,there exist rather wide ductile shear zones. Also,a set of structural windows and klippen are distributed along the zone. The distance of the dislpacement is estimated at about more than 20km. This discovery provides strong evidence for the existence of a latitudinal compressed belt, and shows a considerable shortening of the crust in the meridional direction since the end of Paleozoic.