摘要
油洞断裂是长江铀矿田NW向主断裂之一,研究和勘查程度相对较低。通过对该断裂的构造变形特征、演化特征以及含矿特征的详细评价和研究工作,认为:油洞断裂是一条多期活动的构造带,在110~70Ma之间发生了右行韧性剪切作用,断裂内花岗岩和辉绿岩均发生糜棱岩化,韧性变形自NW向SE逐渐增强,韧性变形的温度为280~350℃,形成差压力为62.6~118.1MPa,平均值为81.4MPa,水或流体对岩石的弱化和蚀变作用可能促进了岩石韧性变形的发生。韧性剪切作用破坏岩石的结构完整性而形成构造薄弱面,从而使其张裂、破碎,成为含铀热液迁移的通道和铀矿赋存的空间,形成较大规模的工业矿体;同时,韧性剪切带空间上产状稳定,向深部延深较大,对于深部找矿具有重大意义。长江矿田油洞断裂南东段韧性剪切作用最强的地段是进一步深部找矿的重要方向。
The Changjiang uranium orefield is one of the most important uranium resource bases in south Zhuguang area. At present,the exploration mainly focuses on NNW trending tensional structural belt. The NW trending Youdong fault is one of the main faults in this area,which is relatively low in research and exploration level. In this paper,detailed structural deformation characteristics,evolution characteristics and ore bearing characteristics of this fault are evaluated and studied. The results show that Youdong fault is a relatively shallow directed dextral ductile shear zone,which occurred between 110~70 Ma,after the mafic vein invasion and before uranium mineralization. The temperature rises to 250~350 ℃ and the pressure to 62.6~118.1 Mpa,averaging 81.4 Mpa. The dultide transformation may be related to the weakening effect of water or fluid on rocks. After the ductile shear action,uranium-bearing siliceous filling mineralization occurred,and then processes of directed dextral brittle shearing and repeated extrusion and nappe occurred. Because ductile shear action can enhance the permeability of the rock,which make the transformed rock easier to form the migration channel for uranium ore-bearing fluid and the store space of uranium ore,thus forming a relatively large scale industrial ore body. Meanwhile,the ductile shear zone is stable in occurrence and lohgen and wider in extention,therefore,the ductile shear zone is a great significance for deep ore prospecting. This paper points out that the area with the strongest ductile shear action in the southern and eastern section of Youdong fault in Changjiang orefield is an important direction for further prospecting.
作者
刘军港
李子颖
聂江涛
金念宪
赵宇霆
陶意
LIU Jungang;LI Ziying;NIE Jiangtao;JIN Nianxian;ZHAO Yuting;TAO Yi(Beijing Research Institute of Uranium Geology,CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology,Beijing 100029,China)
出处
《铀矿地质》
CAS
CSCD
2019年第4期199-205,共7页
Uranium Geology
基金
国家重点研发计划项目“华南热液型铀矿基地深部探测技术示范”(编号:2017YFC0602600)资助
关键词
长江铀矿田
油洞断裂
韧性剪切带
深部找矿
Changjiang uranium orefield
Youdong fault
ductile shear zone
deep exploration
