辽宁西部八家子多金属矿田控矿构造型式

ORE-CONTROLLING STRUCTURE PATTERN OF BAJIAZI POLYMETALLIC OREFIELD IN WEST LIAONING

本文分析了八家子多金属矿田的地质构造特征,提出该区的构造型式为一个滑脱—逆冲推覆构造。它是在北西问南东方向的侧向挤压作用下,由八家子附近的中上元古界与古生界地质块体,沿着与基底花岗岩的界面自北西向南东滑移造成的。主要表现特征是:在前缘形成了呈铲式的收缩型滑脱断层、逆冲断层等挤压性构造,在后缘则出现张裂带并陷落成盆地,两侧发育具有转换断层性质的走滑断层。逆冲断层及边界走精断层是区内主要控矿构造。八家子滑脱—逆冲推覆构造的主要活动时期为三叠纪晚期,结束于早侏罗世。

Studies on the characteristics of the geological structures of Bajiazi polymetallic orefield show that the structure pattern is a slip-thrust nappe structure which is the result of Mid-Upper Proterozoic and Palaeozoic geologic body near Bajiazi slipping from NW to SE along the boundary with basement granite due to the NW-SE lateral compression.In the front,there are compression structures,such as shovel-like shrinkage slip faults,thrust faults etc.;in the back,there are tension-fault-belt and downcast basin,on both side,there are transform-fault-type strike-slip faults.Thrust- faults and strike-slip faults are the major structures in the studied area.The active period of Bajiazi slip-thrust nappe structures mainly ranges from the late stage of Triassic to Early Jurassic.