赣南打古寨复式花岗岩体的解体及其地质意义

Disintegration of Daguzhai Composite Pluton in South Jiangxi and Its Geological Implication

打古寨复式花岗岩体处在江西省宁都县桃山复式岩体北东部,位于桃山铀矿田内,出露面积约30 km2,岩体内分布5个铀矿床及众多异常点、带,但打古寨复式岩体尚未达到彻底解体的深度,各侵入体含铀性及其与铀成矿关系缺乏系统研究。文章根据侵入体-单元-序列的侵入岩填图方法体系以及岩石成分、结构构造、侵入接触关系等,将打古寨岩体划归中-晚侏罗世侵入时序,共圈定侵入体7个、建立单元4个,归并为打古寨岩石序列。在此基础上综合研究认为:铀矿高度集中分布在打古寨序列中是多因素决定,构造是主要因素,且与岩浆活动关系密切;构造活动产生岩浆,并为铀成矿提供成矿空间,伴随岩浆活动带来铀成矿物质,当岩浆活动中心迁移到打古寨岩体,岩浆分异作用完全,铀在岩体中富集成矿。

Daguzhai composite granite body is located in the north-east part of Taoshan composite body in Ningdu County,with an exposed area of 30 km2,It is the host body of Taoshan uranium ore field.there are five uranium deposits and many abnormal points in the body.However,Daguzhai composite pluton has not completely disintegrated,and the uranium bearing characteristics of each intrusion and its relationship with uranium mineralization were not studied systematically.According to the principle of tectonic magmatic evolution stages and petrology,petrochemistry,isotope chronology,contact relationship between pluton and strata.Daguzhai composite pluton has been disintegrated in detail and remerged into one intrusion sequence in Middle-Late Jurassic.A total of 7 intrusions have been classified into 4 units and 1 lithological series.On this basis,the highly concentrated distribution of uranium deposits in the Daguzhai was believed to be determined by multiple factors.Structure is the main factor that provides space for mineralization,Magmatic activity provided ore-forming materials.The activity center gradually migrated to Daguzhai area which resulted in the full magmatic differentiation and uranium enrichment.