北山南带西段金成矿带控矿因素、找矿标志及远景区划分

ORE CONTROLLING FACTORS,SIGNS FOR PROSPECTING AND THE DIVISION OF PROSPECTING AREAS OF WESTERN METALLOGENIC BELT OF SOUTH BELT IN BEISHAN,GANSU

通过对北山南带西段金矿的成矿环境和控制因素的分析,讨论了矿床的成矿时代和空间分布规律。区内金成矿主要受地层岩性、岩体和构造控制。奥陶系、石炭系和二叠系富金的火山—沉积岩为金矿的矿源层,晚加里东—海西期花岗岩侵入体与金矿密切相关,深断裂和区域性大断裂控制了矿带部位。这些矿带由一系列不同成因和不同类型的金矿床组成,金矿床是在矿源层、矿源岩的基础上,经过海西期构造—岩浆活动的改造和富集而形成。依据找矿信息及化探异常、重砂异常的分布范围,提出16处具有较大金资源潜力的找矿远景区。

This paper deals with the metallogenic environment and ore controlling factors of gold ore deposits in western section of south belt of Beishan. In addition, their minerogenetic epoches and temporal-spacial distribution regularities are also discussed. The ore-formation of gold is controlled by lithology, rock body and structure. Ordovician, Carboniferous and Permian Au-rich volcano-sedimentary rocks are the source bed; Late Caledonian-Hercynian granite series correlate closely with the gold deposits; Deep faults or large regional faults control the mineralization zones. The gold ore belt consist of a series of gold deposits of different genesis and types. The gold deposits were formed on the foundation of the source beds and source rocks though reworking and enrichment of Hercynian structure-magmatic activities. Based on new progress and information on prospecting and anomalies of geochemistry and heavy concentrate, and its distribution, it is concluded that sixteen prospecting regions for ore-search are the favourable localities for gold deposits, where there are more potential of gold resources. Breakthrough in gold prospecting in the area might be achieved through detailed geological work and integrated study.