胶东三山岛-仓上断裂带控矿规律与找矿勘查实践

Ore-Controlling Regularity and Prospecting Practice in the Sanshandao-Cangshang Fault Zone,Jiaodong Area

三山岛-仓上断裂带是我国著名胶东金矿集区重要的金矿成矿带之一;近十年来,地勘单位与科研院校针对该成矿带深部资源的预测与勘查做了大量的工作,并提出了阶梯式成矿模式。三山岛-仓上断裂带断裂带主裂面整体较陡,主要沿不同岩体的接触面进行展布,从上至下整体呈现逐渐变缓的趋势,构造蚀变带纵向上呈"S"型或反"S"型的张裂处为成矿提供了有利空间,区域内金矿体主要赋存在主裂面的下盘。对断裂带宏观和微观地质特征的分析显示,断裂带北部在三山岛地段走向NE以张剪性为主,赋存矿体延深大于延长;而在南部新立地段和仓上地段之间断裂带走向近NEE以张性为主,赋存矿体延长大于延深。针对三山岛-仓上成矿带南部与北部成矿地质条件的差异性,有针对性布设探矿工程,南部布设工程走向间距可大于倾向间距,钻孔相对较浅;北部布设工程倾向间距可大于走向间距,钻孔相对较深。

The Sanshandao-Cangshang fault zone is a major gold metallogenic belt in the famous Jiaodong gold mine,Shandong Province. In recent ten years,geological prospecting units and scientific research institutions have done a lot of work on the prediction and exploration of deep resources in this metallogenic belt,and put forward a model of ladder-type mineralization. The main fracture surface of this fault zone is generally steep,extending along contact surfaces of different rock masses,becoming gradually gentle down from top to bottom. The"S"-type or anti-"S"-type tensile fractures in the longitudinal direction of the tectonic alteration belt provide favorable space for mineralization,and the gold ore bodies in the region mainly occur in the footwall of the main fracture plane. Analysis of the macroscopic and microcosmic geological characteristics of the fault zone indicates that the northern part of the fault zone trends in NE in the Sanshandao section,dominated by the extension and shear,and the vertical extension of the ore body is greater than its horizontal range. In the south,the fault zone between Xinli and Cangshang section strikes nearly in NEE,dominated by extension,and horizontal extension of the orebody is greater than its downward depth. In view of the difference of the metallogenic geological conditions between the south and the north of this metallogenic belt,a prospecting scheme is suggested that shallow boreholes should be drilled in the south with larger survey-line intervals in horizontal direction than vertical direction and deeper boreholes should be drilled in the north with larger survey-line intervals in the vertical direction than horizontal direction.