浙东火山岩型银矿成矿条件及勘查方法

本区火山岩型银矿赋存于上侏罗—下白垩统陆相火山岩中;由于中生代太平洋板块向西俯冲.大陆边缘火山岩浆活动强烈.嵊县—黄岩地区由于断裂为造、火山岩发育而形成南北向的矿化集中区.成矿与火山岩浆活动晚期的潜火山岩、脉岩有关.属于浅成中低温热液矿床.根据矿床围岩蚀变、矿化类型及成晕元素的分带规律,可指导找矿及预测隐伏矿床.并初步建立了勘查模式.总结了成矿预测、综合找矿、详细评价三个层次的勘查方法.

ON METALLOGENIC CONDITION AND PROSPECTING METHODS FOR SILVER DEPOSITS OF VOLCANIC-HOSTED TYPE, EASTERN ZHEJIANG

The silver deposits of volcanic-hosted type in the area occur in terrestrial volcanic rocks of upper Jurassic -lower Cretaceous Systems. Due to the westward subduction of the Pacific plate in Mesozoic Era, the volcanic magmatism activatedviolently on the continental margin, and a concentration area of mineralization was formed along Chenxian-Huangyan area with North-South direction, where fault structure and volcanic magmatism are well developed. The metallogenesis was related to the sub-volcanics and vein rocks of the later volcanic magmatism. The deposits are of the epithermal deposits with low-medium temperature.Zoning regularities of alteration of the country rocks, types of mineralization and halo-forming elements of the deposits can be used as indicators for prospecting and predicting some buried ore deposits. Based on them, the prospecting model is preliminary established. The methods of prediction, comprehensive prospecting and detail evaluation of the deposits are summarized in this paper.