福建紫金山矿田罗卜岭斑岩型铜钼矿地球化学立体探测示范

罗卜岭矿床是与晚中生代花岗闪长斑岩体有关的隐伏斑岩型铜钼矿床,矿区位于紫金山矿田的东北部;铜钼矿体主要产于绿泥石化-绢英岩化和(弱)钾化-绢英岩化带中,矿石矿物组合为黄铜矿+辉钼矿;少量过渡类型矿体产于高级泥化带中,矿石矿物组合为蓝辉铜矿+铜蓝+辉钼矿.罗卜岭矿区的原生晕地球化学三维模型显示,微量元素具有一定的分带特征,低温元素Au与高温元素组合W、Sn、Bi分布于矿体上方,中低温元素Pb、Zn、Ag分布于Cu、Mo元素之间;元素直观垂向分带序列大致为:(As、Sb、Hg)-(W、Bi、Sn)-Ga-Au、Ba-Cu、Ag-Pb、Zn-Mn-Mo;前缘晕的元素与氧化物组合为As、Sb、Au、Ga、Al2O3,矿体近矿晕元素组合为Ag、Pb、Zn,缺失尾晕元素组合;Cu、Mo可直接作为找矿指示元素,Au、Ag、Pb、Zn、As、Sb、Ga、Ba、Mn可作为间接指示元素,矿床深部K2O正异常与Al2O3负异常可作为斑岩型铜钼矿的重要找矿标志,这一规律对紫金山矿田深部和外围隐伏斑岩型矿体的勘查工作具有重要的参考意义.

The Demonstration of 3D Geochemical Exploration in the Luoboling Porphyry Cu-Mo Deposit, Zijinshan Orefield, Fujian Province

Located in the northeast of the Zijinshan orefield, the Luoboling deposit is generally a buried porphyry Cu-Mo deposit associated with the late Mesozoic granodioritic porphyry. In the deposit, major Cu-Mo orebodies, with the ore mineral assemblage of chalcopyrite-molybdenite, occur in the chlorite-phyllic and weak potassic-phyllic alteration zones. The minor transitional orebodies, characterized by the digenite-covellite- molybdenite assemblage, are hosted in the advanced argillic alteration zone. The primary halo geochemical 3D model of the Luoboling deposit shows that the trace elements have the characteristics of zoning. Low temperature element Au and high temperature element combination W, Sn, Bi are distributed over the orebody, while medium and low temperature elements Pb, Zn and Ag are distributed between the elements of Cu and Mo. The intuitive vertical zoning of elements is roughly divided into (As, Sb, Hg)-(W, Bi, Sn)-Ga-Au, Ba-Cu, Ag-Pb, Zn-Mn-Mo, with leading edge halo elements and oxide combination being As, Sb, Au, Ga and Al2O3. The near-ore elements are Ag, Pb and Zn, and the tail halo elements are absent. Cu and Mo can be directly used as the indicator elements for prospecting, whereas Au, Ag, Pb, Zn, As, Sb, Ga, Ba and Mn can be used as the indirect indicator elements. K2O positive anomaly in the depth of the deposit and Al2O3 negative anomaly can be used as the important prospecting indicators for porphyry Cu-Mo deposits. These metallogenic rules are important for the exploration of the concealed porphyry orebodies in the depth and the periphery of the Zijinshan orefield.