新疆伽师砂岩型铜矿地质特征及找矿标志

GOELOGICAL CHARACTERISTICS AND PROSPECTING INDICATIORS OF SANDSTONE COPPER DEPOSIT IN JIASHI OF XINJIANG PROVINCE

新疆伽师砂岩型铜矿区位于塔里木盆地西北缘柯坪古生代前陆盆地西南，北部以哈拉峻-阿合奇断裂为界，与南天山晚古生代陆缘盆地相邻，是塔里木北缘的一个陆内海盆。砂岩铜矿赋存于一套主要由褐红色-红色砂岩、粉砂岩、砂质泥岩及泥岩组成的红色砂岩建造中，其中夹有浅灰色砂岩层，铜矿化即发育于浅灰色砂岩中。含矿层长3km，厚4-6m，共发现有3条矿体。其中Ⅰ号矿体长650m，厚2．21～5．13m，平均厚度3．93m，Ⅱ号矿体长190m，厚2-4m；Ⅲ号矿体长100m，平均厚度3．37m。通过对矿区的地层、构造，铜矿体的规模、形态、产状的分析认为，古近系的浅灰色钙质砂岩为找矿的最有利层位；孔雀石化的含岩屑钙质细砂岩转石是找矿的直接标志；膏岩建造一般位于含矿层的底部，石膏层为明显的找矿标志。

Jiashi copper deposit area is located in the south - west part of Paleozoic Keping foreland basin which is an intracontinent sea basin in the northwest Tarim Basin, with north boundary of Halasuo - Aheqi Fault and neighbor to later Paleozoic south Tianshan epicontinental basin. The sandstone copper deposit is hosted in a red sandstone formation which is composed of dark red and red sandstone, siltstone, sandy mudstone and mudstone, parting with light grey sandstone bed where copper mineralization occur. 3 ore bodies have been discovered in ore bed with thickness of 4-6m and length of 3km. Ⅰ ore body is 650m long with average thickness of 2.21-5.31m, Ⅱ ore body is 190m long with thickness of 2-4m, Ⅲ ore body is 100m long with average thickness of 3.37m. By analyzing strata and structures of mine area, scale, shape and occurrence of copper deposit, it is proposed that Neogene light - grey calc- sandstone is most favorable bed for prospecting, cale fine sandstone floater with malachitization is the direct prospecting indicator, and gypsolith is an obvious indicator because it always is underlain ore bed.