湘西自治州北部铅锌矿找矿标志及找矿远景区

TARGET AND CRITERIA FOR LEAD-ZINC ORE PROSPECTING IN NORTHERN PART OF XIANGXI AUTONOMOUS PREFECTURE

湘西自治州北部铅锌矿带,处于桑植复向斜西南段,长100km以上,宽50km左右,矿带内铅锌矿点广布,受地层、构造、岩性的控制。上寒武统耗子沱群至下奥陶统大湾组共有7个含矿层位,北东向背斜倾伏端及北东向断裂、层间裂隙以及次级北西向横跨背斜是矿床控矿构造,有矿体赋存的含矿层有明显的硅化作用,且硅化体中Pb,Zn,Cu明显富集,分别为地层的66、32、8倍,Sr/Ba比值为0.60,无矿存在的硅化体则Pb,Zn,Cu含量接近地层或稍高于地层,Sr/Ba比值高达1.15。在砂子坡背斜南翼、红岩溪背斜北东端和南西倾伏端、盐井背斜,下奥陶统红花园组顶部含矿层内为找矿远景区。

The northern Xiangxi lead-zinc ore zone is located in the southern part of Sangzhi synclinorium, more than 100 km long, about 50 km wide. Mineralizations are distributed extensively in the ore zone,and are controlled by stratigraphic, structural and lithological factors.There are 7 ore-bearing horizons in the sequence from Haozituo Group of Upper Cambrian to Dawai Formation of Lower Ordovician. The plunging crown of NE trending anticlines, NE trending faults, interlayer fractures and the secondary NW cross anticlines are the ore-controlling structures of the deposits. Obvious silisification occurs in the ore-hosting horizons, and Pb, Zn, Cu become obviously rich in the silisified bodies, reach 66, 32, 8 times respectively the contents in the corresponding strata, and the Sr/Ba ratio is 0.60.The ore-barren silisified bodies contain Pb,Zn, Cu near or a little more than the strata, and the Sr/Ba ratio is as high as 1.15. The top ore-bearing horizon of Honghuayuan Formation of Lower Ordovician in the southern wing of Shanzipo anticline, the northeastern end and southwestern plunging crown of Hongyanxi anticline and the Yanjing anticline are the targets for ore prospecting.