Fariba Asiay Soufiani; Hossein Kouhestani; Amir Morteza Azimzadeh
Abstract
Qarachilar Cu-Mo-Au mineralization is located within the Qaradagh batholite in the Arasbaran metalogenic zone. This area is a part of southern margin of Lesser Caucasus. Qaradagh batholite at the Qarachilar mineralization area composed of granodiorite- quartz monzodiorite (as the main phase and host ...
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Qarachilar Cu-Mo-Au mineralization is located within the Qaradagh batholite in the Arasbaran metalogenic zone. This area is a part of southern margin of Lesser Caucasus. Qaradagh batholite at the Qarachilar mineralization area composed of granodiorite- quartz monzodiorite (as the main phase and host rock of mineralization), diorite, quartz monzonitic stocks, apophyses of porphyritic granite and acidic to intermediate dykes. These intrusions have Upper Eocene- lower Miocene age. All of the mentioned intrusion phases have calc-alkaline to high-K calc-alkaline nature and classified as metaluminous I-type granites. The porphyritic granite apophyses and dykes, and quartz monzonitic stocks have adakitic nature and can be classified as high silica adakites. Chondrite normalized REE patterns in granodiorites- quartz monzodiorites indicate enrichment in LREE and flat trend in MREE and HREE, while porphyritic granites show steep pattern with enrichment in LREE and depletion in HREE. Based on field investigation, geological, petrological, geochemical and tectonomagmatic discrimination diagrams, it can be conclude that granodiorite- quartz monzodiorite phase was formed in active continental margin as a result of Neo-Tethyan ocean subduction beneath the Eurasia. The quartz monzonite stocks and porphyritic granites were formed in a post collisional setting from metasomatized lithospheric mantle wedge.
M.A.A Mokhtari; H Moinvaziri2; M.R Ghorbani; M Mehrpartou
Abstract
Au-Cu-Mo mineralization of Aniq-Qarachilar area is located in Arasbaran ore zone within the Qaradagh batholith. Mineralization in this area mainly includes Au-Cu-Mo bearing quartz veins within the granodiorite that cropped out in three areas include: Qarachilar (2 major veins), Zarlidareh (8 veins) and ...
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Au-Cu-Mo mineralization of Aniq-Qarachilar area is located in Arasbaran ore zone within the Qaradagh batholith. Mineralization in this area mainly includes Au-Cu-Mo bearing quartz veins within the granodiorite that cropped out in three areas include: Qarachilar (2 major veins), Zarlidareh (8 veins) and Qaradareh (some narrow and short veins). Alterations around the quartz veins include sericitic and silisification that has limited development. Quartz veins have compact, boxwork and brecciated texture. Sheeted veins of quartz present in some areas especially in the Qarachilar area. Sulfide mineral content of these veins commonly less than 10 percent and includes pyrite, As- bearing pyrite, chalcopyrite, molybdenite, bornite, stibnite, sphalerite and galena. Secondary minerals include coveline, malachite, azurite and iron hydroxides. Geochemical studies and grades of elements indicate that Au, Ag, Cu and Mo have high content in quartz veins. The average grade for Au in two quartz veins in the Qarachilar area is 5.76 and 3.9 ppm. The average grade for Au in the quartz veins in the Zarlidareh area is 4.7, 3.12, 2.6, 0.45, 1.09, 1.34, 1.15 and 0.58 ppm. The highest Au grade is about 359 ppm that belongs to a quartz vein with boxwork texture in the Zarlidareh area (ZV1). Moreover, W and Bi have high concentration in some veins. There is a good correlation between Au and Ag, Mo, W and Bi. Au grades in the Qaradareh quartz veins is low, but Mo grades vary between 0.15- 1.15%. Mineralization as silisic sheeted veins within the granodioritic intrusion, low concentration of sulfide minerals within the quartz veins, limited alteration aureole, Au mineralization together with Mo mineralization and high concentrations of Bi and W and relatively good correlation of Au with Ag, Bi, W and Mo indicate that Au mineralization in the Aniq-Qarachilar area can be classified as an intrusion related gold systems.
