江西冷水坑层控型矿床中碳酸盐岩夹层的特征及其对成矿作用的贡献

摘要

江西冷水坑层控型铅锌矿赋存于上侏罗统铁锰碳酸盐岩夹层中，其品位明显高于斑岩型矿床。根据井下观察及矿区资料发现，研究区碳酸盐岩夹层发生了强烈的碎裂岩化，而碳酸盐岩夹层上下的凝灰岩层或斑岩则基本没有发生碎裂岩化。根据相关资料，不同岩石具有不同的抗张抗剪强度，碳酸盐岩的抗张强度明显低于凝灰岩和斑岩的抗张强度，因此认为研究区高品位的层控型矿床主要赋存于碳酸盐岩夹层中，是因为在张性构造运动下，碳酸盐岩夹层先于其上下的凝灰岩或斑岩发生碎裂岩化，含矿热液更容易进入碎裂岩化的碳酸盐岩夹层中；而碳酸盐岩又具有高的可溶性，为含矿溶液的沉淀增加了更多的空间，因而进一步提高了层控型矿床的品位。%Lengshuikeng stratabound deposits lies in upper Jurassic iron and manganese carbonate intercalation .Its ore grade is higher than the porphyry deposits obviously .Based on the geological data of borehole and mining area , the iron and manganese carbonate intercalation have formed cataclastic lithification seriously , while the tuffs beds or the porphyry around the iron and manganese carbonate intercalation have not form Cataclastic lithification a little . According to relevant information , different rocks have different tensile strength and shear strength ,and the tensile strength of carbonate is lower than the tensile strength of tuffs and porphyry clearly .So we suggest that when the tensional tectonic movement occurred ,the iron and manganese carbonate intercalation got to form cataclastic lithification first because of the lower tensile strength ,and then the ore forming fluids feed into faulted structural zones .The carbonate is soluble which makes the grade of Ag-Pb-Zn Ore Deposit in iron and manganese carbonate intercalation higher than in other rocks around obviously .