摘要
辽北太古宙由花岗岩-绿岩带组成。绿岩生成于岛弧构造环境,时间在3.0—2.8Ga,火山岩属拉斑玄武质及钙碱性火山岩。花岗岩在绿岩之后侵入,具多旋回特点。块状硫化物矿床与长英质火山岩有关,具有2—3含矿层位,透镜状矿体数目较多,未发现管状细脉带。矿石中Cu>Zn>>Pb,具有明显贫铅的特点,Cu×100/Cu+Zn为88—25。矿床类型属活火山型火山热液矿床。成矿温度为350—250℃,压力为9.5—4.0MPa,fo_2为10^(-30)-10^(-44)Pa,fs_2为2.57×10^(-9)-8.13×10^(-14)Pa,pH值为4.5—5。共生有阿尔戈马型铁矿与火山成因金矿。块状硫化物矿床遭受变质、变形、伟晶岩的改造,并在主褶皱幕期迭生与基性岩有关的热液多金属矿化。
Archaebzbic in North Liaoning is composed of granite-greenstone formed in the tectonic environment of island arc during 3.0-2.8 Ga.The granite intruded after the forming of greenstone,with the.characteristic of polycycle.Massive sulphide depbsits(MSD) are concerned with felsic volcanic rock, belonging to the series of the thol(?)itic and calc-alkaline volcanic rocks.It has 2-3 ore-bearing beds and more lensoid ore bodies but no pipe-like veinlet belt.The ores arc poor in lead obviously (Cu>Zn≥Fb), and the value of Cu×100/(Cu+Zn)is 88-25. MSD intergrowing with Algoma-typc iron deposit and volcanogcnic gold deposits belong to the volcanic hydrothermal deposits of the active volcano-type.The minerogenetic temperature, pressure, oxygen fugacity, sulfur fugacity and pH of the deposit are about 350-25℃,9.5-4.0MPa,10^(-30)-10^(-44)Pa,2.57×10^(-9)-8.13×10^(-14)Pa,4.5-5 respectively.MSD is remaked by metamorphism,deformation and pegmatization,and telescoped the hydrothermal polymetallic mineralization concerned with basic rocks in the period of principal folding phase.
关键词
绿岩
块状
硫化物
矿床
火山热液
North
Liaoning
Archaeozoic
Greenstone
Massive sulphide deposit
Volcanic hydrothertnal