关于岩浆热液矿床形成的几个问题——以斑岩型矿床为例

岩浆在其放气作用过程中能向地表释放出大量的金属元素，如Ｃｕ、Ｍｏ、Ａｕ，如果存在适当的富集机制，从而浆熔体中释入出来的成矿元素在一定的地质环境中聚集并沉淀就能够形成工业矿体。岩浆液态不混溶作用是导致分散于岩浆熔体中的成矿元素有效富集并最终形成工业矿体的重要机制。

Some problems concerning the formation of magmatic hyrrothermal deposits

Through convecdon,hydrothermal system derived from magmatic fluids causes the diffusionof large proportion ofheat from the depth of the earth to the surface. At the same time,these flu-ids transport metals,forming a very important class of ore deposit ,namely hydrothermal deposits. Porphyry copper and molybdenum deposits,for example ,provide more than half of these metalsfor the world.Magmatic fluids serve as the major source for many components in hydrothermaldeposits. These components consisting of metallogenic elements and their carriers find their waysto and eventually get concentrated in magmatic fluids. Under low pressure(e. g. in a volcanic envi-ronment),some ore- forming elements such as Cu,Au,Mo and S might get concentrated in mag-matic fluids,which,in turn,can form economic deposits once the proper mechanism for metallicconcentration comes into being.In addition,the immiscibility of magmatic liquids might cause theseparation of the magmatic system into two immiscible parts:silicate melt and fluids,with the lat-ter being enriched in ore-forming elements and volatiles,In this paper,the following points areemphatically pointed out:( 1 )ore-forming elements in hydrothermal deposits are derived dircctlyfrom magma;(2)magmatic fluids play a leading role in the formation of hydrothermal deposits;( 3)magmatic liquid immiscibility seems to be an important factor causing ore-forming elements tobe separated from silicate melt and get concentrated;( 4 ) though closely associated with mineral-ization,alteration is not the cause responsible for the ore-forming process.