Position relative to mineralization surface based on supra and sub-ore elemental halos in the Gowdal copper skarn, north of Ahar, NW Iran

The copper skarn deposit at Gowdal is located in northeast of Shivardagh batholithic body, north of Ahar, East-Azarbaidjan Province. The Shivardagh intrusive body is a part of the magmatic belt of the Alborz-Azarbaidjan-Lesser Caucasus which in turn is related to the magmatic arc of the Meso-Tethys Ocean. The skarn mineralization of copper, iron, and molybdenum (chalcopyrite, pyrite, molybdenite, magnetite, and specularite) occurred particularly in exo-skarn zone at the contact of this igneous body with limestone- marly limestone unit. Also, the supergene copper-iron minerals (malachite, azurite, and Fe-hydroxides) superimpose the hypogene skarn mineral assemblages. Based upon statistical studies carried out on the data obtained from core logs, copper has very good correlation with silver and good correlation with gold and nickel and these elements are reckoned to be as elemental paragenesis in the Gowdal ore body. In addition, consideration of multiplicative geochemical haloes of elements in the supra-ore (Pb×Zn×Sb) and sub-ore (Cu×Ag×Ni) showed that the greater and more notable haloes of supra-ore elements belong to the near-surface horizons while the bigger haloes of sub-ore elements are observed in the lower horizons of the ore body. The function of erosion in the southwest of deposit caused the ore body to be situated in its present level, and the ore body displays the evidence of hidden mineralization toward northeast. On the other hand, considering the minimum and maximum values of the geochemical zonality indices (0.0016-27) in the present level and the elevation levels of the boreholes, the ore body has a northeastward dip.