辽西火山岩型金矿地质特征及成因讨论

辽西火山岩型金矿分布在中生代陆相火山盆地边缘活动带内,受辽西弧形构造带控制,为火山期后热液矿床,可初步划分为3种成因类型:次火山(斑岩)热液型(二道沟式),火山—次火山热液型(红石砬子式)和爆发角砾岩型(水泉式),成矿作用与中酸性火山—次火山岩关系密切,成矿时代为燕山期(90—110Ma)。稳定同位素研究结果表明,含矿热液为富含挥发组份和多金属成矿元素的富金水溶液,来源于地壳深部或上地幔,即高温热卤水对镁铁质、超镁铁质岩石长期侵蚀、淋滤和溶解,获取大量的金属成矿元素,在不透水层之下形成深部液态矿源层。

GEOLOGICAL CHARACTERISTICS AND GENESIS OF VOLCANIC GOLD DEPOSITS IN WESTERN LIAONING PROVINCE

Controlled by an arcuate zone, volcanic gold deposits in western Liaoning province occurred in the mobile belt on the margin of Mesozoic continental volcanic basins. It is of postvolcanic hydrothermal deposits and can be divided into 3 genesis types: subvolcanlc (porphyry) hydrothermal type (Erdaogou-type), volcanic-subvolcanic hydrothermal type (Honjshilazi-type), and explosion-breccia type (Shuiquan-type). The mineralization is closely related with intermediate-acid volcanic-subvolcanic rocks and the metallogenetic epoch is Yanshan-stage. Studies on isotope of stable elements show that the ore hydrothermal from deep crust or upper mantle is rich in volatile component and polymetallic ore-forming elements, especially gold element. The hoe-brine eroded, leached and dissolved femic and ultramafic rocks, and obtained a large amounts of metallic ore-forming elements, then a liquid source bed formed in the depths under impermeable layers.