桐柏-大别碰撞造山带大型推覆-滑脱构造及其演化

桐柏-大别山是从志留至三叠纪连续发展演化的碰撞型造山带,以大规模推覆-滑脱构 为特征,推覆距离可达140km。造山带可分为超叠陆壳、混杂岩片及俯冲陆壳三个构造单元。地层对比、同位素年龄及变形分析可追溯其演化史:晚元古代泛中国板块解体;志留纪末期,古特提斯洋壳俯冲消减;石炭纪时,扬子与华北板块碰撞,陆间俯冲开始,华北板块推覆到扬子板块北缘之上;三叠纪末,形成前陆褶冲带;侏罗-白垩纪以来,造山带收缩隆起,伴随岩浆活动,大型走滑断裂及断陷盆地。

THE LARGE THRUST-DECOLLEMENT STRUCTURE AND ITS EVOLUTION OF TONGBAI-DABIE COLLISION TYPE OROGENIC BELT

The recent works demonstrate that the Tongbai-Dabie Range (T-DR), eastern segment of Qinling mountains in central China, is a collisional orogenic belt characterised by large thru-st-decollement with at least 140 km of horizontal transport. It is composed of the collisional melange, subducting continental crust, thrust-over continental crust, relic sea molasse forma-, tion and foreland fold belt. Its main tectonic evolution can be subdivided into 4 periods: 1), the disintegration of Pan-China Plate, and the formation of Palaeotethys ocean crust before early Palaeozoic; 2), ocean-continental subduction during late Silurian-Devonian; 3), intercontinental subduction and large shallow crustal deformation from the end of Devonican to Carboniferous; 4), since late Jurassic the range has upwarped and has been sliced by huge east west sinistral strikeslip faults.