论贵东岩体东西部花岗岩岩石学特征和铀成矿条件差异性

通过对贵东岩体花岗岩岩石学特征和铀地球化学性状的系统研究,认为贵东岩体主体花岗岩是由有一定时间间隔的三期花岗岩在空间上的复合,即东部的下庄岩体、东南部的鲁溪岩体和西部的隘子岩体,三期花岗岩为不同源区地壳物质部分熔融的产物。东部下庄岩体的富铀性和铀的强烈活化,使它成为该区唯一有利的成矿铀源体,阐明了贵东岩体东部成矿西部不成矿的根本原因,指出今后的找矿重点还应放在东部地区。

ON THE DIFFERENCE OF PETROLOGICAL CHARACTE- RISTICS AND CONDITIONS FOR URANIUM METALLO- GENESIS BETWEEN THE EASTERN AND WESTERN GUIDONG GRANITE MASSIF

Through the systematic study on petrological characteristics and geochemical behaviour of uranium in Guidong granite massif, it is considered that the main phase of granite intrusion in Guidong massif was a special superimposition of three stages of granite intrusion with some time intervals, that is, Xiazhuang massif in the east (196 Ma), Luxi massif in the southeast (185 Ma) and Aizi massif in the west (157 Ma). These three stages of granite were formed by partial melting of different crustal materials derived from various provenances. High uranium content and strong uranium mobilization of Xiazhuang massif in the east caused it to become the only uranium source favourable for uranium mineralization. The essential reason why uranium deposits occur in the east and not in the west of Guidong massif has been expounded and it is pointed out that emphasis should be placed on the east of the massif for exploration in the future.