三山岛断裂在海域北延位置的确定及成矿预测

发布时间：2018-06-08 18:58

本文选题：三山岛断裂 + 金矿　；参考：《地质学报》2017年12期

【摘要】：胶东金矿集中区是中国最重要的黄金基地,三山岛金矿带位于该金矿集中区之胶西北成矿区的西部,近年来深部和海域隐伏区找矿取得重大突破。作为该区域重要的赋矿构造,三山岛断裂带进入海域后向两端延伸位置未能确定。为了查明三山岛断裂在南北两端进入海域后的延展位置,使用海底重力仪开展了海上大比例尺重力测量工作,对其位置进行了推断。在布伽重力异常图上,三山岛断裂表现为规模大、水平变化率大的重力梯级带,在平面上呈"S"形,向北由三山岛金矿延伸入海,向南从新立西延入渤海,跨海后经仓上、潘家屋子东延入渤海。为了确定三山岛断裂带向北东方向穿过三山岛北部海域超大型金矿床后的延展位置,根据重力异常推断的三山岛断裂北延位置,结合该金成矿带地质矿产特征,部署钻孔进行验证。钻孔内主要岩性有中细粒(含黑云母)二长花岗岩、钾化二长花岗岩、碎裂状二长花岗岩、绢英岩化花岗岩等,暗色脉岩有辉长岩及少量黑云母闪长岩、闪长玢岩等,其中暗色矿物黑云母等略具定向排列,脉岩均发生不同程度的蚀变。构造蚀变(矿化)带宽206.25m(876.59~1082.84m),与上盘围岩分界较为清楚,与下盘围岩呈渐变关系,圈定7层矿体,累计厚度28.3m,最厚的单层矿体视厚度16.06m。钻孔位置位于重力梯度变化宽缓的"鼻状区",且空间位置符合等距分布、对应产出、分段富集等分布规律,钻孔中见到多为黄铜矿化、方铅矿、黄铁矿等多金属硫化物矿化,为典型的第一矿集群特征,可以确定该地区继三山岛北部海域470吨超大型金矿发现之后,其北部区域又出现一个很有找矿前景的靶区。
[Abstract]:Jiaodong gold concentration area is the most important gold base in China. The Sanshandao gold belt is located in the west of Jiao northwest metallogenic area. In recent years, great breakthroughs have been made in the prospecting of deep and hidden areas in the sea area. As an important ore-hosting structure in the region, the location of the extension of the Sanshandao fault zone into the sea area at both ends has not been determined. In order to find out the extension position of the Sanshan Island fault after entering the sea area at the north and south ends, the work of large-scale gravity survey on the sea was carried out by using the submarine gravimeter, and the position of the fault was inferred. On the gravity anomaly map of Buga, the Sanshandao fault shows a gravity cascade belt with a large scale and a large horizontal change rate, with a "S" shape on the plane, extending north from Sanshandao gold deposit into the sea, moving south from Xinli Xi into the Bohai Sea, and crossing the sea through the barns. Pan's house runs east into the Bohai Sea. In order to determine the extension position of the Sanshandao fault zone after it passes through the super-large gold deposit in the northern sea area of Sanshan Island in the northeastward direction, according to the gravity anomaly, the location of the north extension of the Sanshandao fault is inferred and combined with the geological and mineral characteristics of the gold metallogenic belt. Drill holes are deployed for verification. The main lithologic features in the borehole are medium-fine-grained (including biotite) monzogranites, potassium monzomorphic granites, cataclastic monzomorphic granites, sericite granites, etc., dark dike rocks include gabbro and a small amount of biotite diorite, diorite porphyrite, etc. Among them, dark mineral biotite and other slightly directional arrangement, dikes occurred varying degrees of alteration. The band width of structural alteration (mineralization) is 206.25mU 876.59U 1082.84mW, which is clear to the upper wall rock and has a gradual change relation with the lower wall rock. Seven ore bodies with accumulative thickness of 28.3m and the thickest monolayer orebody with apparent thickness 16.06m are delineated. The location of the borehole is located in the "nose region" with a wide and slow gravity gradient change, and the spatial position accords with the distribution law of isometric distribution, corresponding to the distribution of production and enrichment, etc. In the borehole, it is found that most of the holes are chalcopyrite, galena, pyrite and other polymetallic sulphide mineralization. For the typical characteristics of the first ore cluster, it can be determined that after the discovery of 470 tons of super large gold deposits in the northern part of Sanshan Island, there is a promising target area in the northern part of the area.
【作者单位】：山东省地质调查院;
【基金】：国家重点研发计划专题项目(项目编码:2016YFC0600107-2) 中国地质调查局地质矿产调查专项项目(项目编码:12120113060400;12120114034901)资助的成果
【分类号】：P618.51

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