湘黔地区“卡林型”金矿中金的赋存形式

对矿石的化学物相分析结果表明，湖南─贵州─带“卡林型”金矿原生矿石中的金主要呈微粒状单质金被包裹于硫化物及以绢云母为主的粘土矿物中，反映了金的矿化作用与黄铁矿化和绢云母化等是同时发生的。不同的“卡林型”金矿床之间，由于形成的物理化学条件的差异，其主要载金矿物的种类也不相同。表生氧化带中，载金矿物硫化物和绢云母发生了氧化和分解作用，使矿石中的大部分金转化为游离态形式存在，提高了矿石的可选性。

Modes of Occurrence of Gold in the Carlin-Type Gold Deposits of Hunan-Guizhou Area

In recent years,several Carlin-type gold deposits have been found inHunan-Guizhou area. Some of these deposits are stratiform ones on tops of thepaleokarst denudation planes,and others are tabular ones eXtending alongfaults.Chemical phase analysis was carried out to study the mode of occurrenceof gold in the gold deposits,and the results show that,in primary ore,thecontent of free gold is very low,with above 9 5%of gold encapsulated inpyrite and sericite.In ore deposits on tops of the paleokarst denudationplanes,sericite is the most important carrier of gold.whereas in the ore depo-sits within the faults,pyrite is the most important carrier of gold.The closespatial association of gold with pyrite an6 sericite suggests that the depositionof gold was synchronous with the growth of pyrite and tbe recrystallizationof sericite. The gold microparticles encapsulated in minerals can not be leachedby cyanidation.In the supergene process pyrite and sericite in primary ore are oxi dizedand decomposed, The gold microparticles encapsulated in those minerals arereleased and then accrete into larger particles.In oxidized ore,80%of gold isfree gold,and thus the economic value of the ore improves greatly.