赣南上围地区控矿断裂特征与铀成矿关系

    The characteristics of ore-controlling fault and its relationship to uranium mineralization in Shangwei area, Southern Jiangxi Province

    • 摘要: 位于江西省龙南县上围地区出露的燕山期花岗质复式岩体明显受北东向马屎山硅化断裂带和鹅形石英断裂夹持控制,是有利的产铀岩体,已探明291铀矿床和292矿点。岩体内断裂作用强烈,热液蚀变和铀矿化现象普遍。经地质调查,在岩体内识别出北东向断裂6条和北北东向断裂11条及若干北西-北西西向断裂。其中,北东向断裂主要包括岩体西部的硅化带和东部的石英断裂;北北东向断裂主要包括岩体东部的蚀变碎裂岩带和西部硅化破碎带;北西-北西西向断裂多被中基性岩脉充填,主要包括501~504号脉。北北东向断裂与铀成矿关系最密切,是容矿断裂。断裂的规模和产状控制了铀矿体的空间分布和展布形态,断裂性质控制了铀矿化类型,断裂变形程度控制铀矿化蚀变分带,断裂与中基性岩脉复合控制了富铀矿体的产出形态。

       

      Abstract: Shangwei area is in southernmost Longnan County, Jiangxi Province. The Yanshanian Shangwei granite complex pluton is strictly controlled by NE-trending Mashishan fault zone and Exing fault and occurs in the NE-trending oval form. It is a uraniumbearing granite body, where there exist known uranium deposit No. 291 and No. 292 uranium ore spot. Due to strong faulting, alterations and mineralizations are abundant in main fault belts. Geological survey reveals that the fracture tectonic system in Shangwei area is mainly formed by 6 NE-trending faults, 11 NNE-trending faults and some NW-NWW trending faults. The NE-and NNEtrending faults include silicified fault (QF3, QF4), quartz fault (QF7~QF9), silicified fractured fault (QF1, QF2, QF5 and QF6) and altered cataclastic fault (F1, F2, F3 and F7). The NW-trending fault is usually filled with intermediate basic veins (501~504). NNE-trending faults are intimately related to uranium mineralization, and are thus the main ore-bearing faults. Uranium orebody occurs within the NNE-trending faults and bears a close relation to silicified breccia and cataclastic altered rock. The attitude of NNE-trending fault controls the dip of the orebody, its property controls the mineralization types, the deformation behaviour controls the horizontal zoning characteristics of mineralization and alternation, and the fault and the veins obviously control the shape of rich uranium orebody.

       

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