周至马鞍桥金矿控矿规律及成矿预测研究

【作者】 黄喜峰；

【导师】 钱壮志；

【作者基本信息】 长安大学 ， 矿物学、岩石学、矿床学， 2004， 硕士

【摘要】 位于陕西周至县境内的马鞍桥金矿床，区域构造隶属于秦岭海西褶皱带北部边缘，含矿地层为上泥盆统的桐峪寺组，容矿岩石为细碎屑岩。区内岩浆活动较强烈，变质作用和后期热液活动明显。矿区围岩蚀变较发育，金的品位较低。 矿区现分为东、中、西三个矿段。区内断裂构造发育。矿体受韧性剪切带控制，以似层状、透镜状赋存于泥盆系与石炭系间的层间断裂带中。金的富集严格受多级构造控制，区域性韧性剪切带控制了矿床的展布，而次级韧脆性剪切带控制了富矿体的分布，后期的脆性构造对矿体有一定的改造、破坏作用，同时也加强了金的再一次富集。强烈的构造变形即是金矿床形成的主导动因。矿床属于韧性剪切型金矿，韧性剪切带既是导矿构造，也是控矿、容矿构造。 韧性剪切带型金矿中金的富集不仅在应变最强部位或韧性向脆性转换的部位，还可以在强变形带与弱变形域交接的部位。 论文是在广泛收集前人资料的基础上，通过野外实地调查和室内研究完成的，结合秦岭地区区域地质条件和地质背景，论文提出在沙梁子—双庙子和庙沟—小王涧两区域性断裂之间，板房子—小王涧复向斜北翼的旭奋子—黄石板次级构造是主要的控矿及导矿构造，并通过构造的产状效应分析对矿区深部肓矿体做出推测： 金矿脉展布在K20、K19、K25异常附近，并在香沟矿段K19号1150中段，蚀变指标有减弱趋势，可推测深部矿体无太大的延伸。在大崖沟1430中段发现蚀变矿化带，其中黄铁矿化较强烈，为下一步的找矿提供了有利的地段。 同时，论文在马鞍桥金矿矿床成因问题上做了初步的探讨，并提出本区金矿物质部分来源于幔源的新认识。更多还原

【Abstract】 Maanqiao gold deposit is located in Zhouzhi county, Shaanxi province. It is on the north edge of Vaviscian fold belt in Qinlin. Ore-bearing stratohorison is Tongyusi group of late Devonian system and ore-bearing rock is minute clastic rock formation. In the area, magma action is strong, metamorphism and hydrothermal action is evident. Wallrock alternation is wide spread. The tenor of gold is low.There are three parts in mine-east, middle and west. Faults are wide spread in the area. The orebodies controlled by ductile shear zone, which are lenticular and bedded, are in interlayer fault zone between Devonian system and Carboniferous system. The enrichment of gold is under the control of polyfactor-the outspread of the ore bed is controlled by the regional ductile shear zone, the rich orebody is controlled by the accessorial ductile-brittle shear zone, and the succedent brittle shearing formation break the mineral to some extent, also has some favorable function to the enrichment of gold. Strong transformation of geology is the main reason of the gold deposit’ formation. The ductile shear zone is not only the ore-leading and ore -controlling structure , but also the ore-bearing structure.In the gold deposit which belongs to the ductile shear zone, there is rich gold deposit not only in the zone where there is strong transformation or where the ductile of fault shear zone changes to the brittle shear zone, but only in the belt where there is weak transformationThe dissertation is on the basis of collecting predecessors’ achievement, and brings to success by field autoptical and studies in doors. By researching geology condition and geology background, it is concluded that the main ore-controlling ore-leading structure is The accessorial formation of Xufenzi-Huangshiban, which is to the north of Banfangzi-Xiaowangjian, which is in the fault belt between Shaliangzi-Shuangmiaozi and Miaogou-Xiaowangjan.It is also concluded that the ore bed in the depths of K20, K19 and K25 are rich. It is predicted that it is difficult to forming ore beds in the depth of K19 because the index of wallrock alternation decreases. A lot of iron pyrites in the meddle of 1430 near ore bed in Dayagou can be found , which is the next foreground of finding ore.At the same time, the dissertation has also made a discuss about the genesis of the ore bed and brings forward a new idea that partial aurum of the gold deposit comes from the mantle.更多还原