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.