中国陆相火山岩型金矿床找矿模型

中国陆相火山岩型金矿床目前发现两种类型。１．金银矿床组合类型，以黑龙江团结沟金矿床为代表；２．金铜矿床组合类型，以福建紫金山金铜矿床为代表。两类矿床的特征模型不同，因此其找矿模型也有明显区别。前者的找矿前提是陆内深断裂分布区的陆相火山岩盆地，沿火山喷发中心多期侵入的次火山斑岩体，矿体产于晚期岩体顶部和边部的爆破角砾岩简内；其找矿标志是玉髓状石英硅化带，向下有冰长石－绢云母型的蚀变分带，典型的矿石组

PROSPECTING MODEL FOR CONTINETAL VOLCANIC GOLD DEPOSITS IN CHINA

Two types of continental volcanic gold deposits have been fund in China,i.e.An-Ag and An-Cu represented by Tuanjiegou deposit in Heilongjiang province and Zijinshan deposit in Fujian province.The prospecting models of two types are different due to various features.The prerequisite of prospecting An-Ag type of deposits is subvolcanic porphyry bodies multiphasely intruding around the volcanic center in continental volcanic basin.The ore bodies were located on the top of the later in trusions and in the explosive breccia pipes.The prospecting criteria of this type are St alternation zone consisting mainly of chalcedonic quartz, below which are adular-sericitic alternation zone and their typical ore textures as well as typomorphic minerals.In geochernical nomalies of primary halo,Hg-Ah-As belongs to head halo,An-Ag belongs to middle halo and Bi belongs to rear halo, which.can be served as impotant information for prospecting this type of deposits,while,the prerequisite of prospecting An-Cu deposits is continental volcanic conduct or dome in the transitional belt between upwelling and depression on the margin of ancient continent.In such types,ore bodies are often found in intrusive contact.zone of multiphasely shrinking volcanic bodies.Criteria for prospecting this types of deposits are double alternation zones in the upper part of which is sericitization,dickitization,alunitization,and in the lower part of which Kfeldspar,biotization,crocidolitization are found. There are siliceous breccia types of gold lode.in the upper part and porphyry types of Cu-No in the lower part.In geochernical nomalies of primary halo,An-Ag belongs to rear halo.Based on above prerequiaites and criteria,by using corresponding techllological methods,an efficient prospecting result could be attained.