小秦岭金矿田北矿带大湖、灵湖深部金矿控矿构造与蚀变特征

F5矿脉是小秦岭金矿田北矿带内最主要的金矿脉,已经发现的金金属资源量达68.042 t。矿脉东西全长11 km以上,北倾,倾角15°～45°,局部可达50°以上,在走向及倾向均具明显波状起伏、分枝复合特点,构造带宽度40～150 m,带内岩石以糜棱岩、碎裂岩、碎裂岩化岩石为主。本文对大湖和灵湖段的F5构造特征进行深浅部对比,认为大湖矿区的金矿体主要赋存于F5糜棱岩带内的张性构造面中,而灵湖矿区,金矿赋存于靠近顶板和靠近底板的糜棱岩带中。两个矿区的主要矿体均产于F5中,但其形成机制显然不同,大湖矿区是在韧性变形形成糜棱岩之后,发生逆冲构造活动形成的张性构造面成矿。灵湖矿区的成矿可能与糜棱岩带与围岩界面所形成的地球化学障有关,又受向北西扭冲形成的张性裂隙控制。

Deep ore-controlling structure and alteration characteristicsof deep part of Dahu and Linghu gold deposits in north belt of Xiaoqinling

The F5 vein is the most important vein in the north ore belt of Xiaoqinling gold field, The discovered gold and metal resources are up to 100 t. With a total length of more than 11 km from east to west, a north dip angle of 15°~45°. It has obvious undulation, branching and composite characteristics in strike and trend. The width of structural belt is 40-150 m, and the rocks in the belt are mainly mylonite, cataclasite and cataclasite. In this paper, the deep and shallow comparison of the structural characteristics of F5 in the Dahu and Linghu section shows that the gold ore bodies in the Great Lakes mining area are mainly located in the tensile structural plane in the F5 mylonite belt, while in the Linghu mining area, the gold ore bodies are located in the mylonite belt near the roof and floor. The main ore bodies of the two mining areas occur in F5, but their formation mechanism is obviously different. The ore-forming mechanism of the Dahu mining area is the tension structural plane formed by thrust tectonic activity after the mylonite formed by ductile deformation. The mineralization of Linghu mining area may be related to the geochemical barrier formed by the interface between mylonite belt and surrounding rock, and also controlled by the tensile fracture formed by the NW thrusting.