皖南中生代构造运动新认识

NEW RECOGNITION ON THE MESOZOIC TECTOGENESIS IN SOUTH-ANHUI

皖南在中生代太平洋板块剧烈活动期间受到由南(东)向北(西)的应力挤压,形成近东西向的隆起。结品基底由南向北推覆,而隆起带中及南侧的部分浅变质岩系及其上沉积盖层沿基底及层间滑脱面产生由北向南的重力滑动,后缘形成褶皱。侏罗—白垩纪,皖南发生多次被动拉张的断陷盆地,前缘加厚并形成(倒转)褶皱。侏罗—白垩纪,皖南发生多次强度不同的多层次滑脱—逆冲推覆作用并伴随岩浆活动,到晚白垩世发生由南东向北西的大规模逆冲推覆构造,从而完成皖南中生代板内造山过程。

The movement of the Pacific Plate during Mesozoic had a great influenced upon the South Anhui and extruded it from south (or southeast)to north (or northwest), the South Anhui, in turn, produced nappe struture and forced uplift run nearly east to west. When the southern part of the crystalline basement thrusted northward, the sedimentary cover, including some element of basement, slid gravitatively from north to south on basal surface or layer surfaces (i. e. multilayer detachment surface) in zone of uplift. At the back of deteched bodies there were the passive tensile fault basins, in the front of it became thickening and forced reverse fold. During Jurassic and Cretaceous Period, tectogenesis occurred, meanwhile changed its direction, time and again from multilayer detaching to nappe thrusting and vise versa strongly or weakly, followed by the magma movement. By the stage of Cretaceous the wide scope nappe structure happened northwestward and finished in—plate orogenic process.