鄂西北竹山银洞沟银金矿床构造控矿特征

银洞沟银金矿床位于扬子地台北缘武当推覆体西部，产于武当群变火山岩组与变沉积岩组间的顺层型韧性剪切带中，与构造变形密切相关。晋宁期的伸展作用产生了顺层型韧性剪切带，韧性变形变质作用促使原岩中银金等贵金属、多金属元素活化迁移，随剪切变形变质热液在强应变带中沉淀，形成初始矿源层。印支期的陆陆碰撞作用，促成不同层次面型剪切带岩石褶皱、韧脆性推覆，成矿元素从初始矿源层中再次活化、运移，随着沿褶皱轴面劈理发育的烟灰色糜棱岩化石英脉的形成，沉淀富集于石英脉中，形成银金矿床。脆性变形的叠加，使含矿石英脉产生扭动，促使成矿元素的局部富集，形成透镜状或板状矿体。成矿元素的垂直分带是由构造环境的变化导致成矿元素的叠生作用而形成的。多硅白云母及白云母年龄的测定表明该矿床的成矿期为印支期。

CHARACTERISTICS OF STRUCTURALLY CONTROLLING MINERALIZATION IN THE YINGDONGGOU SILVER GOLD DEPOSIT, ZHUSHAN, NORTHWEST HUBEI

The Yingdonggou silver gold deposit, located in the west of the Wudang nappe,north margin of the Yangtze platform, is a large scale of superimposed multiple metal deposit, which occurs in the place that shows intense ductile shear zone between the meta volcanic rocks and meta sedimentary rocks. The deposit can be divided into three mineralization stages: (1) primary mineral layers forming in ductile shearing, Ag, Au, Pb and Zn enriching in the fine grained quartz veins developing parallel to the axial plane of the Yingdonggou antiform in the period of ductile brittle shearing, (2) silver gold bodies resulted from the elements enriched locally under the action of brittle shearing, and (3) the evidence of Ag, Au, Pb and Zn elements showing belting with Ag Au and Ag Au Pb and Pb Zn downwards also indicates the records from superimposed mineralization. The main mineralization was dated in the Indosinian movement according to the(216 68±3 75)Ma from muscovite in the veins and(292±4 76)Ma from phengite in the ductile brittle shear zones.