山东平度旧店金矿田帚状构造成因及控矿特征分析

旧店金矿田位于招平断裂南端,矿田内矿床均受旧店帚状构造控制,分析该帚状构造特征认为,其主要受3期不同作用力叠加而成：侏罗纪晚期—早白垩纪早期（160～125 Ma）,受太平洋板块向欧亚板块的NW向覆冲作用力,是平面具左旋特征的帚状构造主形成阶段;白垩纪中期（125～100 Ma）,郯庐断裂的伸展与燕山期地幔热柱强力侵位作用造成了剖面上的帚状构造;白垩纪晚期（100～80 Ma）,郯庐断裂全面拉伸对前期各构造改造阶段。该帚状构造内的NNE向东倾的压扭性构造为主要控矿构造,经主要矿床的深部验证证实,此类构造深部赋存较好的隐伏金矿体。

On genesis and ore control characteristics of brush structure for Jiudian gold field in Pingdu of Shandong

Jiudian gold field was located in the south end of Zhaoping Structure,its ore deposits were controlled by Jiudian brush structure. By analysis of the brush structure,the author told that it was formed by superimposition of different acting forces in three stages： nappe action in the Pacific plate to Eurasian plate in NW strike during late Jurassic to early Cretaceous period（ 160 ～ 125 Ma）,and was the main forming stage for brush structure with flat and levo-rotary characteristics; middle Cretaceous（ 125 ～ 100 Ma）,the extension of Tanlu fault and strong emplacement plume in Yanshan period resulted the brush structure on the profile; late Cretaceous（ 100 ～80 Ma）,Tanlu fault full stretch brought a tectonic reworking stage of the structures. The author summarized the compressive structure that sloping towards the east of NNE was the main ore control structure. It was concluded that concealed gold ore body was occurred in the deep parts of such types of structures through deep validation.