Economic Geology
Meysam Nikfarjam; Ardeshir Hezarkhani
Abstract
In this research, we have used different integration methods for creating the geochemical evidential map that is one of the most important layers in mineral potential mapping. The Study area (Varzaghan 1:100,000 sheet) is located in East Azarbaijan province and Ahar-Arasbaran metallogenic zone. This ...
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In this research, we have used different integration methods for creating the geochemical evidential map that is one of the most important layers in mineral potential mapping. The Study area (Varzaghan 1:100,000 sheet) is located in East Azarbaijan province and Ahar-Arasbaran metallogenic zone. This region, because of its geological situation and presence of several porphyry copper deposits like Sungun porphyry-skarn deposit, is considered as an important metallogenic province in the northwest of Iran. In this study, we have used 1067 stream sediment samples as primary data that picked up by Geological Survey & Mineral Explorations organization of Iran. By selecting indicator elements of porphyry copper deposit, like Cu, Mo, Au, Ag, Pb, Zn, Au and As, the evidential map of each element have generated by the continuous fuzzy method. In the next step, by using Union Score (US) method, fuzzy OR operation, and geometric average, the individual geochemical maps have integrated. Finally, Prediction-Area plots have drawn to validate the evidential maps. This plot showing that geochemical evidential map that produced by US method, can predict 76 percent of known mineral occurrences and it can consider as a proper method for creating the geochemical evidential map for porphyry copper deposits.
Economic Geology
Meysam Nikfarjam; Ardeshir Hezarkhani; Kaveh Pazand
Abstract
The study area (Varzaghan 1:100,000 Sheet) is located in eastern Azarbaijan province and Ahar-Arasbaran metallogenic zone. The magmatism in this area is happened widespreadly that leads to several important deposits like Sungun world class deposit. According to the importance of this region from Cu-Mo ...
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The study area (Varzaghan 1:100,000 Sheet) is located in eastern Azarbaijan province and Ahar-Arasbaran metallogenic zone. The magmatism in this area is happened widespreadly that leads to several important deposits like Sungun world class deposit. According to the importance of this region from Cu-Mo porphyry deposits, we used structural methods like multifractal method to determinate Cu and Mo geochemical anomalies as indicator minerals of Cu-Mo porphyry deposits. In this paper two multifractal method like C-A (Concentration-Area) and N-S (Number-Size) method were used in order to separation geochemical anomalies from background and select the optimum method. In this way, first of all, we draw catchment basins for every stream sedimentary samples by using DEM and PFS (Priority-First-Search) algorithm. After drawing the catchment basins for each sample, concentrations of samples were assigned to their upstreams. In C-A method with plotting cumulative area of each sample catchment basin versus concentration content, 4 number society of each Cu and Mo elements identified. Also in N-S method, cumulative frequency of concentrations versus concentrations plotted. In this method in comparison to C-A method, 5 number society of Mo and 4 number society detected. In both performed methods can see good conformity of anomalous locations with well known deposits like Sungun worldclass deposit but N-S method has better efficiency by using logratio matrix. Also we can see the effect of lithology in anomalous places. Finally some of theses places addition to indications detected. So they require detailed exploration in future.
