NAPPE TECTONICS IN ANHUI

Nappe structures are very well developed in Anhui. The relative typical ones include the Heifengling, Tongshan, Xiangquan, Yinpingshan, Zhangjiashan, Hexishan, Huolonggang and Jiulianshan nappes. The on-the-spot investiga- tions, drilling, data of its neighbouring regions, regional structures, nature of structural movements and environments in which magmatic rocks were formed ——all this shows that these nappes were mostly formed in the Early Cre- taceous to early Late Cretaceous and were mainly the products of the middle and late Yanshanian movements. According to their directions, the nappes may be grouped into two sets, the N-S set and the NWW-SEE set. The former only has a small displacement, while the latter has moved for 5--12km. The nappes in the region are usually closely associated with regional thrust faults and vortex structures. From this it is judged that the former is of compressive type, while the latter compresso-shear type, both of which resulted from me- ridional crustal shorthering and horizontal compression derived from relative motion of the easten and western massifs in Anhui.