浙江永嘉下龙银金矿蚀变分带及矿床成因

浙江永嘉下龙矿区属火山岩型金属矿床。分析下龙矿区银金地质特征和蚀变分带，发现矿区蚀变垂直分带有一定的规律性，自上而下分为绿泥石蚀变带、石英-绢云母-黄铁矿蚀变带、黄铁矿-绿泥石-碳酸盐蚀变带3个带，其中石英-绢云母-黄铁矿蚀变带蚀变在空间分布上与金银矿体分布一致，成因上与成矿密切相关，是该区良好的直接找矿标志。成矿作用与金银丰度较高的西山头组控矿层位、构造、潜火山岩侵入密切相关，矿床成因为中低温火山热液蚀变型矿床。研究其地质特征和成矿规律，可为该地区寻找同类型矿床提供借鉴。

Alteration zoning and metallogeny of Xialong silver-gold deposit in Yongjia, Zhejiang Province

Xialong silver-gold deposit falls into the metal deposit of volcanic rock type. Based on the summary of the geological characteristics and alteration zoning of Xialong silver-gold deposit in Yongjia, this paper found that its vertical alteration zoning can be regarded as a proper direct prospecting sign due to its regularity. Specifically, it includes 3 belts of chlorite alteration zone, quartz-sericite-pyrite alteration zone, and pyrite-chlorite-carbonate alteration zone, where the second zone is spatially consistent with the silver-gold ore bodies, thus bound up with mineralization. The metallogeny is closely related to the ore-controlling horizon of the Xishantou Formation with high gold-silver abundance, tectonics and the intrusion of subvolcanic rocks. The genesis of the deposit is volcanic hydrothermal alteration of mesothermal-epithermal origin. The study of geological characteristics and metallogeny could provide certain guidance for exploring deposit of the same type.