摘要:
甘肃省合作市早子沟金矿床是西秦岭地区近年来发现的规模达到百吨级别的矿床.该矿床金矿体受构造控制作用明显, 因此开展控矿构造研究, 可为矿区勘查找矿工作提供指导.本文主要是在野外实地对控矿断裂构造详细观测分析的基础上, 利用构造解析法、节理分析法、共轭剪节理法和断层擦痕分析法, 通过吴氏网投图分析, 确定了早子沟金矿床多期次构造活动的主应力方向, 并根据叠加和切割关系以及成岩成矿时代的确定, 推断了应力作用的期次和时代.根据分析结果, 将早子沟金矿的构造应力场划分为3期5个阶段: 成矿前的基底变形、区域变形和岩浆侵位阶段, 早期和晚期成矿阶段, 以及成矿期后阶段, 矿体局部被错断.结合成矿作用特征, 进一步分析了不同阶段断裂活动与成矿关系, 认为构造应力场演化与成矿作用具有一致性,并指出了NE向主断裂与旁侧分支断裂的复合部位以及NE向断裂与NW向断裂的交会部位是矿区深部寻找富大矿体的有利空间.
Abstract:
Located in western Qinling Mountain, the Zaozigou gold deposit in Hezuo City of Gansu Province is one of the recently discovered large-reserves deposits. Orebodies are mostly hosted in fault zones, showing that the mineralization was tightly controlled by fault activities, and the research on ore-controlling structures can provide scientific guidance for ore-prospecting in the mining area. Joints and scratch lineations in the deposit were detailed measured in the field in order to identify the principal stress direction by traditional and modern methods of tectonic stress field and to divide the stage and time of the tectonic stress field by the tectonic superposition, conjugating relation and diagenetic ages of magmatic rock and mineralization. The tectonic stress field in the Zaozigou area can be divided into three stages and five periods. Basement rocks were deformed, regional deformation occurred and magma emplacement took placed before the mineralization. The main mineralization stages could be divided into two periods. Orebodies were locally dislocated by fault activities after the metallogenesis. The relationship between tectonic activities and mineralization characteristics were further discussed, and the results suggest that the evolution of the tectonic stress field was consistent with the mineralization. In addition, favorable structural ore-forming areas in the depth are further pointed out.
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