甘肃玉门—肃南地区砂岩型铜矿赋矿地层特征及其归属

Stratigraphic Features and Belongingness of Sandstone Type Copper-Deposit in Yumen-Sunan Area of Gansu

玉门—肃南地区为北祁连西段海相砂岩型铜矿成矿区。区域地层主要为早古生代海相火山-沉积建造。区内天鹿、干沟-老虎沟、牦牛沟、天桥湾、三把羊、红口子6个铜矿床(点)均赋存于下古生界上部地层中。以往对其时代归属存有争议。笔者对区内4个铜矿区的赋矿地层及代表性矿床——天鹿铜矿、鹿角沟及天涝池实测剖面地层特征进一步研究表明,区内砂岩铜矿赋矿地层在岩石组合和地层层序、地球化学等方面与上部晚志留世地层有比较显著的差异。根据区域对比研究表明,区内砂岩铜矿赋矿地层应归属泉脑沟山组上段,时代应为中志留世。

Yumen-Sunan is a metallogenic province of marine sand stone-type copper deposit in the west section of northern Qilian area.During Early Paleozoic era,the strata in this area were mainly the marine volcanic-sedimentary formation in the Six copper deposits（spots） of Tianlu,Gangou-Laohugou,Maoniugou,Tianqiaowan,Sanzhiyang,and Hongkouzi,all in the upper part of lower Paleozoic strata.The belongingness of their age remains controversial.Through further study of stratigraphic features of measured section of Tianlu copper deposit,the,author think that the rock composition,stratigraphic sequence,and geochemistry of ore-containing strata of sand stone type copper deposit in this area are distinctly different from that of the upper stratigraphy of late Silurian Epoch.According to regional comparison,the ore-containing strata of sand-stone type copper deposit of the area are the upper member of Quannaogoushan Formaition,belonging to the middle Silurian.