摘要
易门凤山铜矿床是赋存于中元古界昆阳群中的中型富铜矿床。它是位于刺穿构造内，以原始铜沉积为基础，受构造控制的后期叠加改造富化矿床。含矿地层是中元古界昆阳群因民组三段上部和落雪组下部地层。岩性主要是褪色白云岩、泥质白云岩、炭质白云岩和白云质韵律砂板岩和因民角砾岩。矿床位於由小绿汁断裂、三家厂断裂和Ｆｌ１纵断裂所组成的三家厂刺穿体的南部。刺穿体形态为南北向的倒“楔子型”，入刺穿体内的因民组和落雪组构成一个同斜的、南部翘起的复式向斜。刺穿体被—组ＮＷ向断裂切错。主要矿体赋存於同斜复式向斜内次级背斜鞍部和次级向斜轴部，受一组与次级背向斜轴向一致的断裂及派生的断裂、裂隙控制，呈似层状、透镜状产出。矿成作用主要有三期：早期以浸染状矿化为主，属同沉积阶段形成，已保存甚少；中期以细脉、网脉为主，是主要成矿期；晚期以块状大脉为主。中期成矿矿石矿物主要是斑铜矿。黄铜矿，见斑铜矿交代黄铜矿，斑铜矿中有出熔叶片状、蝌蚪状黄铜矿。单矿物爆裂温度为３５０℃左右。δ３４Ｓ值—１１．２１～＋２５．９２％，硫是多来源。黄铜矿含金最高达２３．６ｇ／ｔ。据围岩和矿石的微量元素分析结果，经数理处理，Ｃｕ、Ｐｈ、Ｚｎ、Ｃｏ、Ａｓ、Ｃｄ，为同空间的组合?
The Fengshan Cu deposit is a medium type of rich Cu deposit existing in Middle Proterozoic Kunyang Group.It is Iocated in a diapiric structure,controlled by structure,with a primary Cu deposition basis,and enriched by the later superimposed reformation.The ore-bearing strata are the upper part of Kunyang Group Yinming Formation 3rd Member and the lower part of Luoxue Formation.And the rocks consist of faded dolomitite,argillaceous dolomitite, carbonous dolomitite,sandy slate with dolomitic rhyme and Yinming breccia.This deposit is in the S part of the Sanjiachang diapiric body formed by Xiaoluzhi fault,Sanjiachang fault and F1 longitudinal fault.The diapiric body looks like a NS reverse 'wedge', the Yinming Formation and the Luoxue Formation involved in it form an congruous composite syncline with a rising part in the south.This dlapiric body is cut by a set of NW faults.The main ore bodies,in lenticular and quasi-bedded forms,exist in the saddle of subordinate anticline or the axis of subordinate syncline of the congruous composite syncline, and are controlled by a set of faults consistent with the axis of subordinate anticline,syncline and the derived faults, fissures.The metallogenesis is mainly divided in to 3 periods.The early ores are mostly disseminated, formed with sedimentation,and rarely remained.The principal metallogenesis takes place in the medium period,most ores form veinlets or network vein.The late ores are mainly in massive big veins.The ore minerals of the medium one mostly consist of bornite and chalcopyrite,we can see the former replace the latter,and there are exsolved foliate or tadpolelike charcopyrite in the bornite.The decrepitation T of monomineral is about 350℃ δ34S value -11.21-+25.92%, indicates the S is polygenetic.The highest An content in charcopyrite is 23.6g/t.According to the mathematical treatment of the trace elements analyses of rocks and ores,Cu,Pb,Zn,Co,As,Cd are an isospace assemblage, there isn t any genetic relation of Cu to them.The main alterations of wall rocks are decoloration,silicification and chloritization.In the Sanjiachang diapir, there are a small amount of Yinming breccia and basic rock veins,which shows the present mining exploitation just reaches its middle part. Because the ore body extends deeply,the reserves can be increased and the deposit probably becomes a large type one.
出处
《云南地质》
1996年第2期164-179,共16页
Yunnan Geology
