地幔热柱多级演化及其成矿控矿研究:以张-宣幔枝构造研究为例

Multiple-stage evolution of mantle plume and its control of mineralization: Taking Zhangjiakou-Xuanhua mantle branch as an example.

张-宣地区是河北省金银多金属矿床集中区,可划分出以宣化—崇礼—赤城一带岩浆-变质杂岩区为中心的金矿集中区和外围盖层区的银多金属矿分布区。近年研究表明,金银多金属成矿物质主要来自地球深部,通过地幔热柱多级演化向上迁移,并在幔枝构造的有利构造扩容带中集聚成矿。分别以幔枝构造核部的东坪金矿、拆离带的黄土梁金矿和外围断陷盆地中的万全寺银金矿为例,通过其成矿作用的解剖、分析、归纳认为,在张-宣幔枝构造展布区,平面上从核部向外围,垂向上由下部往上部,均具有金→银→铅锌矿的分带性,并已经在多处矿山得到采矿工程或钻探工程的证实,这对于深部找矿具有重要指导意义。同时据此分析表明,张-宣幔枝构造区深部仍具有很大的找矿潜力,这种成矿作用分析也可以推广到成矿地质条件相近的幔枝构造区。

Zhangjiakou-Xuanhua area is a gold,silver and polymetallic mineralization concentration area in Hebei.It can be divided into a gold deposit concentration area around the Xuanhua-Chongli-Chicheng magmatic-metamorphic core complex and a silver and polymetallic deposit distribution area in surrounding cover rocks.Studies indicate that the metallogenetic material of gold,silver and polymetallic deposits mainly came from deep Earth.In the process of multiple-stage evolution of mantle plume,they moved up and concentrated as deposits in the favorable structures of mantle branch.This study takes the Dongping gold deposit in the core of mantle branch,the Huangtuliang gold deposit in detachment zone and the Wanquansi silver-gold deposit in surrounding fault depression basin as examples to make analyses on their metallogenesis.It is considered that,horizontally from core to surroundings and vertically from deep to top,there exists zoning character of Au→Ag→Pb-Zn deposits in Zhangjiakou-Xuanhua mantle branch,which has been confirmed by mining engineering and drilling engineering in many mines.This is significant for ore prospecting in deep.So it is proved that there is a great potential in the deep of Zhangjiakou-Xuanhua mantle branch.This approach may also be applied to other mantle branch area with similar geological condition.