华北克拉通和西澳克拉通金矿床对比研究及其对中国金矿勘查的启示

华北克拉通固结时间较晚,活动性较强,金矿床赋矿围岩以中深变质的镁铁质岩石和花岗岩类岩石为主,大规模金矿床一般产在韧、脆性剪切叠加的构造带中,成矿时代在188~46Ma之间.西澳克拉通固结较早,稳定性较好,金矿床主要产在太古宙花岗岩-绿岩地体中,一般产在韧-脆性剪切过渡带或叠加的构造带中,金矿化年龄在2640~2600Ma之间.华北克拉通金矿床比西澳金矿床形成晚,受剥蚀程度低,许多矿床尚未出露地表,在深部寻找盲矿体前景可观.

COMPARISON OF GOLD DEPOSITS BETWEEN NORTH CHINA AND WESTERN AUSTRALIA CRATONS AND ITS GUIDANCE TO GOLD EXPLORATION IN CHINA

North China craton is a later solidified and more active craton,from which more than 50% gold of China is mined Ore host rocks are mainly meso hypometamorphic mafic rocks and granitoid Large scale gold deposits accour in the superimposed structural zones of ductile and brittle shearing Granitoid rocks are broadly distributed in the craton Ore bodies are in stratiform,lens,veins or pipes Most of them are large quartz vein type Mineral compositions are chiefly guartz,sericite,K feldspar and pyrite Au is associated with Cu,Pb,Zn,Ag,W,S,As,Bi and Sb Wall rock alteration types indude silicification,sericitization,pyritization,K feldspathization,carbonation and chloritization The mineralization age is 188～46Ma Western Australia craton is an earlier solidified and stable one Almost 70% gold of the continent comes from W A.Most gold deposits occur in Archeozoic granite greenstone terrains of Yilgarn block.Structurally,major deposits are distributed in the fransitional or superimposed zones of ductile brittle shearing Granitoid rocks occupy Yilgarn block by 2/3 area The occurences of ore bodies in W A craton have no difference from those in N China craton Shear zonal and metasamatic types of deposits are dominated in W A Main minerals in ore are quartz,sericite,albite,chlorite,amphibole,carbonate,pyrite and arsenopyrite Alteration types include pyritization,silicification,sericitization,chloritization,carbonation,albitization and Cr V micatization The mineralization age is 2640～2600Ma Comparing to its counterpart in W A craton,the mineralization in N China craton is much later The craton has undergone less denudation Many deposits have not outcropped The exploration for gold in N China craton is promissing