赣北大湖塘地区燕山期构造—岩浆活动与成矿关系研究

Yanshanian tectono-magmatic activities in the Dahutang region,northern Jiangxi Province and their relation to mineralization

江西大湖塘钨铜多金属矿床(田)成矿地质条件独特且复杂,目前对该区成矿具有重要意义的燕山期构造、岩浆岩缺乏系统研究。在综合已有研究成果的基础上,进一步总结了大湖塘地区燕山期构造—岩浆活动特征,并系统分析其与成矿的关系。燕山期构造—岩浆活动与钨铜多金属成矿作用是该区构造阶段性演化的结果,其中成矿构造经历了"深层次挤压(压缩)→浅层次张裂(伸展)"过程,成矿岩浆—流体经历了"深层次陆壳重熔→中浅层次流体混合—自变交代—卸载成矿"的演化进程,成矿结构面则只经历了"相对封闭—相对开放"的突变过程,它们集中出现在同一构造层次,并在成矿期构造控制下形成了总体规模巨大、钨铜共(伴)生、多种类型复合、平均品位不高,但单体资源储量相差较大、局部特高品位随机产出的大湖塘式钨铜多金属矿床(田)。

The Dahutang tungsten-copper polymetallic ore field in northwestern Jiangxi Province is of unique but complicated metallogenic conditions,and no systematic study has been carried out on the Yanshanian structures and magmatic rocks.Based on the previous researches,this study further summarized the features of Yanshanian tectono-magmatic activities and analyzed their relations with mineralization.It can be concluded that the tungsten-copper polymetallic mineralization was the product of Yanshanian tectono-magmatic activities,with metallogenic structure changing from deep extrusion（compression）to shallow tensile fractures（extension）and metallogenic magmatic fluid also experiencing from deep-seated continental crust remelting to medium-shallow fluid mixing-automatic metasomatism-unloading mineralization.The metallogenic structural planes underwent one process of changing from relatively closure to relatively opening,but occurred in the same tectonic level,resulting in the formation of the structurally-controlled,locally-enriched Dahutangtype tungsten-copper polymetallic deposits（ore field）.The deposits are characterized by large size,tungsten-copper association,multiple-type compound,low average grade,and variable amount of mineral resources.