江西永平铜矿区古构造应力场与构造演化

利用多重反演方法(Multiple Inverse Method,MIM)恢复永平铜矿多期古构造应力场,该方法可以划分形成断层擦痕的多个古构造应力期次.研究表明,永平矿区印支期以来至少受到3期古构造应力场作用,进而探讨了永平铜矿构造演化历史.第一期构造应力场为EW方向的近水平挤压,形成轴向近SN的褶皱,以及走向近南北的逆断层；第二期构造应力场为NW-SE方向近水平挤压,伴随着岩体的侵入,导致层间破碎带的矽卡岩化和矿体形成；第三期构造应力场为EW方向的再次挤压作用,造成控矿断层推覆距离加大,混合岩和矽卡岩破碎带向西逆冲推覆到晚古生代地层之上.

A Study of the Palaeotectonic Stress Fields and Tectonic Evolution in the Yongping Copper Deposit, Jiangxi Province

Multiple Inverse Method is useful for separating stresses from heterogeneous fault slip data. By using the method applied to fault slip data in the Yongping Copper Deposit, three phases of palaeotectonic stress were found since the Indosinian. At first, E W direction of compressive stress field formed S N direction of folds, faults and interlayer fracture zone. Then the tectonic stress field transformed as NW SE direction. Accompanied by the intrusion of pluton, thermal metamorphism occurred on interlayer fracture zone.Hydrochloride rock changed into skarn and mineralization. At last, E W direction of compressive stress leads to increasing nappe distance.As a result, migmatite and skarn thrust over Paleozoic strata from east to west.