印度尼西亚苏门答腊岛浅成低温热液型金(银)矿产资源总量预测

苏门答腊岛位于印度尼西亚西缘,是环太平洋成矿带的重要组成部分,拥有丰富的铜、金、铅、锌等金属矿产资源,对其资源总量进行评价可以为国家“一带一路”倡议决策提供基础数据。在对该区进行野外调查和1∶100万低密度地球化学调查的基础上,分析了小比例尺尺度下浅成低温热液型金(银)矿床的地质特征、关键控矿因素和找矿标志,构建了该类金(银)矿床的预测模型;认为该区NW向苏门答腊大断裂及其次级断裂与新生代岛弧岩浆岩具有密切的时空耦合关系,该断裂系统和新生代岩浆岩共同控制浅成低温热液型金(银)矿床的产出;已知金(银)矿床点和1∶100万低密度地球化学异常可以作为快速圈定研究区有利找矿地段的标志;并据此圈定成矿远景区5个,其中A级成矿远景区3处,B级成矿远景区2处;然后,利用通用密度模型预测了不同概率下的各远景区未知矿床数,并运用蒙特卡罗模拟预测了苏门答腊岛浅成低温热液型金(银)矿产在不同概率下的金(银)资源量。

Quantitative prediction of the undiscovered epithermal gold(silver) mineral resources in Sumatra,Indonesia

Sumatra Island, located on the western edge of Indonesia, is an important part of the Pacific Rim metallogenic belt, and has abundant mineral resources such as copper, gold(silver) lead and, zinc.The quantitative prediction for these mineral resources can provide basic data for the "Belt and Road" strategic decisions of China.Based on the geologic investigations and the 1:1 000 000 low-density geochemical survey, this paper analyzed the mineralized characteristics, key ore-controlling factors, and prospecting indicators for the epithermal gold(silver) deposits, and established a prediction model for this type of gold(silver) deposit.This model suggested that the NW-trending Sumatra fault and its secondary faults have a close spatial-temporal coupling relationship with Cenozoic arc magmatic rocks, and they jointly control the gold(silver) mineralization in this area.The NW-trending faults, the Cenozoic magma rocks, the distribution of gold(silver) deposits, and the 1:1 000 000 low-density Au-Ag-Cu geochemical anomalies can be used to rapidly delineate the prospecting areas of the epithermal gold(silver) mineralization.Five prospecting areas were delineated according to the prediction model.Furthermore, a general density model was used to predict the number of undiscovered mineral deposits in various prospecting areas under different probabilities, and the probabilistic number of the gold(silver) resources were estimated for the epithermal gold(silver) deposits by the "three-part" quantitative assessment method.