中国层控银矿床主要地质特征及分类

矿体含银量>100g/t,其它有益组分不及工业品位,称之为单一型银矿床;矿体含银量>80g/t,其它有益组分达到工业品位,称之为共生组合型银矿床。中国银矿床明显受地层层位控制,其主要赋矿地层有:元古界高于庄组、三岔子组、大石桥组、银洞沟组、歪头山组;古生界为泥盆系。其次为寒武—奥陶系和石炭—二叠系;中生—新生界。赋矿岩石建造主要有5种类型:1.碳酸盐岩;2.中酸性火山熔岩或次火山岩;3.含火山物质的沉积岩;4.沉积碎屑岩;5.变质岩。中国银矿床的形成具长期性和多期次性的特点,其主要表现在岩浆活动、区域变质和构造变动等的改造作用。银矿床的分布基本与活动带的分布区相一致。中国层控银矿床共分四大类和二个亚类。

THE IMPORTENT GEOLOGICAL FEATURES AND CLASSIFICATIONS OF THE STRATA-BOUND SILVER DEPOSITS IN CHINA

According to the collected information, the silver deposits in China are generally divided into two types: the single type that its silver content is more than 100 g/t and the other useful compositions are less than industrial tenor; the paragenesis type that its silver content is more than 80 g/t and the other useful compositions are more than industrial tenor.The silver deposits in China are obviously controlled by the stratas that are mainly Gaoyuzhuang Formation,Sanchazi Formation,Dashiqao Formation, Yindonggou Formation, and Waitoushan of Archean; Devonian System of paleozoic secondly Cambrian-Ordovician System and Carboniferous-Permian System. and Mesozoic-Cenozoic. The silver-bearing formations have five major types:1, carbonate rock; 2, intermediate-acid volcanic rock or subvolcanic rock; 3, sedimentary rock containing volcanic material; 4, sedimentary clastic rock;5, metamorphic rock.The silver deposits are basically distributed along active zones, and formed with the protracted and multiperiod natures showing in the deformations such as magmatic actions,regional metamorphisms and structural movements etc. The strata-bound silver deposits in China are divided into four types and two subtypes.