Geochemical study of major and trace elements and their application in gold exploration in Qolqoleh shear zone (Southwest of Saqez)

Abstract:

Qolqoleh gold deposit is located in northwestern part of Sanandaj-Sirjan zone, and hosted in a ductile and brittle shear zone and is categorized in orogenic gold deposits. Concentration and distribution of elements from the analysis samples collected from trenches perpendicular to ore-bearing zones, showed geochemical changes of major, minor and trace elements in host rock lithologies and encompass ore-bearing zones of different deformation and alteration. According to the present study, silica, iron, copper and potassium of major elements and mercury, arsenic, molybdenum, barium and tungsten of trace elements showed positive correlation with high-grade zones accompanied by deformation and alteration. Calculated correlation coefficients in correlation matrix of elements showed a maximum gold positive correlation with silica, mercury and barium and to a lesser amount with potassium. Moreover, gold showed a weak positive correlation with arsenic, iron, and uranium. According to the calculations, gold showed a maximum negative correlation with chromium, sodium, scandium, lead and zinc and to a lesser amount with aluminum, calcium, cadmium, manganese, magnesium and nickel, and the least negative correlation with antimony, cobalt, strontium and vanadium. Gold, mercury, silicium, iron, sulfur and copper positive correlation showed that gold mineralization and other accompanying elements as well, are the result deposition of silicic fluids containing auriferous bisulfide complexes, during a homogenous alteration in an intensely deformed shear zone. Interesting point is that, the high volumes of LOI indicating the major role of alteration and mineralizing fluids in gold deposition from bisulfide complexes. Mineralogical paragensis consists of pyrite, chalcopyrite, arsenopyrite, pyrhotite, magnetite and sphalerite. It seems that, geochemical variations of major, minor and trace elements in the Qolqoleh gold deposit as sulfide and silicic alteration shear zones of high deformation (mylonite-ultramylonite) and also microfractures, microveins and veinlets can be used an exploratory guide for gold deposit prospecting and exploration of this type.