جستجوی مقالات مرتبط با کلیدواژه « Geochemical haloes » در نشریات گروه « زمین شناسی »

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.

The Garmab Cu mineralization, in the east of Semnan and southeast of Shahroud, is situated in the Eocene conglomerate association with weakly hydrothermal altered. The weak alteration, mineralization and geochemical haloes is locally controlled by faults and late fractures. At the surface, secondary copper minerals including malachite and azurite and in the depth, primary sulfides generally are pyrite, arsenopyrite and chalcopyrite. Gangue minerals of the veins are commonly quartz, chalcedony, opal and minor calcite. Other components contain goethite, limonite and hematite with manganese oxides and minor jarosite smithsonite and gypsum. The results of statistical geochemical analyses indicate a positive correlation between copper with Au, Ag and As. According to host rock, mineralization, spatial relationships and geochemical dispersion patterns, deep drilling is suggested in the depth in the east of mineralization. The study district is related to buried intrusive bodies and epithermal vein-type Cu deposits.