Investigation of structural distribution of gold mineralization in “Sefidsang” area (SE-Zahedan, Iran)

Abstract

Sefidsang area is located 70 km to south east of Zahedan. This area is located in the eastern Iran flysch zone. It has been composed of Ophiolithic rocks and Flysch sediments. Zahedan granitoides of Oligocene age have intruded in these rocks with a NW-SE trend.It within shear zone lies structurally that is among two strike-slip fault (Zahedan and Nosratabad) in east and west respectively. The Zahedan fault with > 150 km length, almost N-S trend and reverse component is strike- slip. The Nosratabad fault with < 200 km length, NW-SE trend and reverse component is strike-slip. The lithic units of this area have been influenced by NE-SW trending of joints and faults. Sampling was considering factors such as stratigraphy, lithology, tectonic and alteration zones. The 60 lithogeochemical samples after preparation were analyzed by AAS method. For 6 selective elements (Au, Ag, Cu, Pb, Zn and As) factors such as frequency distribution, background, threshold, anomaly, enrichment index and mineralization index have been calculated individually and with the separation of lithic units, and the element distribution maps and joints map have been drawn. Therefore spatial location, structural and geochemical distribution and mineralization relationship with structural factors have been determined. The most enrichment index of Au with average 1.70 ppm in siliceous veins have been achieved that these veins emplaced within shear joints that its affected by movements of two Zahedan and Nosratabad main stike slip faults. The same strike of siliceous veins and the main strike of joints and faults in this area show that mineralization is in the control of structural parameters.