摘要
铜陵地区硫化物矿床均赋存于石炭系、二叠系、三叠系海相碳酸盐岩及海陆交互相碎屑岩中,受东西向基底隐伏深断裂带和印支期北东向盖层构造控制。燕山期中性—中酸性岩浆侵入上述岩层和有利空间时,使成矿物质活化、富集而形成有工业意义的同生沉积后改造矿床。控矿岩体中主要造岩矿物斜长石牌号与所形成的矿种有明显的专属性。当斜长石多为中长石,An 值在35～47之间时有利于形成硫铁矿矿床;当An 值减小,以更—中长石为主时,有利于形成铜-硫型矿床;当An 值近于30或低于30,即以更长石或更—钠长石为主时,则有利于形成以铜为主的矿床。
The sulfur-polymental depoists in Tongling district in Anhui province almost alllie in the marine carbonate and marine-land alternating elastic sequences agedCarbonifreous,Permian and Triassic,strictly controlled by the EW-trendingbasement deep faults and NE-striking cover structures of Indosinian epoch.When theYanshanian intermediate-acid magmas intruded into these host sequences,orelsewhere favouring mineralization,the ore-forming materials there were activated,enriched and eventually developed into synsedimentary,then reworked,ore depositsof industrial interest.The principal rock-forming minerals of ore-controlling rockbodies,plagioclases,have a close link with final deposit types in terms of their acidvalues(An).In fact,plagioclases indexed into reange of An=35 to 47,namelyandesine,have a tendency of being associated with pyrite deposits while An-lowerones,usually 26 to 47,such as andesine,oligoclase,etc,affiliate more often tocopper-sulfur type deposits and all kinds of copper deposits.In conclusion,Changesin An of plagioclases in the study area excert a larger impact on what type depositsshould belong to after formation,displaying a clear specialization of An values inmineralization.
