四川拉拉铜矿床成因研究

Study on the Genesis of Lala Copper Deposit, Sichuan Province

四川拉拉铜矿产于古元古宇河口群落凼组 ,成矿围岩为一套细碧角斑质火山岩及以硅质岩、条带状钠长岩和萤石化黑云母岩为主的喷气岩 ,矿体呈似层状、透镜状。矿石呈条带状、浸染状 ,部分呈角砾状 .。矿石矿物呈他形粒状以填隙方式产出 ,并见交代溶蚀结构和黄铁矿的胶状结构。矿石矿物主要为黄铜矿、黄铁矿及少量斑铜矿、辉钼矿。黄铁矿的常量元素、Co/Ni、S/Se均显示火山喷流 -沉积矿床的特征。铅同位素及硫同位素资料表明 ,铜铁等金属物质主要来源于围岩 ,而硫以深源为主 ,并有海水硫酸盐参与。矿床属火山喷流-沉积型硫化物矿床。

Lala copper deposit occurred in Loudang member of Houkuo group of proterozoic. It’s wallrocks are composed of volcanic sedimentary rock and exhalite that is dominated by banded albite and fluoritization biotitite. Ore bodies with banded, disseminated, stringer and anastomosing structure, which conformed with the country rock, are present in the form of strata and lens shaped.Ore minerals are composed of chalcopyrite, pyrite, and minor bornite, molybdenite. Bases on study of sulfur ,lead isotope, the copper and iron in the ore bodies came from wallrock and sulfure derived from deep seated source.The major elements, Co/Ni, S/Se in pyrite indicate that this deposit is of volcanic exhalation sedimental mineralization.