安徽的推覆构造
NAPPE TECTONICS IN ANHUI
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摘要: 安徽的推覆构造十分发育,几乎遍布全省,推覆体多掩盖了原地系统的地质构造面貌,因此,查明推覆构造,对研究区域构造和普查勘探工作都具有重要意义。一、推覆构造简介目前,已初步查明:宿县黑峰岭、夹沟,滩溪县青龙山,肖县相山,淮南洞山,大别山南缘二郎河,来安县凉子山,无为县香泉,巢县银屏山,怀宁县张家山,宿松县破凉亭、河西山,芜湖县火龙岗,宣城县狸头桥—九连山,广德县安凌村—白茅岭,青阳县木钲—泾县摇头岭—宣城县青峰山,祁门—休宁—屯溪—歙县月潭一线等地,均有推覆构造产出,现介绍8个典型实例。 (一)黑峰岭推覆构造Abstract: 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.