Akademik Veri Yönetim Sistemi
CANADIAN MINERALOGIST, cilt.45, ss.1397-1413, 2007 (SCI-Expanded)
Tourmaline is the most common borosilicate mineral in granite-related magmatic-hydrothermal ore deposits in the Aegean region of western Turkey. Hydrothermal deposits there include the mesothermal argentiferous Pb-Zn-Cu deposit at Kadikalesi (Bodrum-Mugla) and the porphyry An deposit at Kisladag (Esme-Usak), with related potassic igneous rocks and accompanying Tertiary strata of western Anatolia. At Kadikalesi, mesothermal vein-type mineralization is linked to monzodioritic intrusions in a subvolcanic suite, which is overlain by volcanic rocks ranging in composition from calc-alkaline to potassic. In the non-brecciated hydrothermal systems, tourmaline occurs as subhedral to anhedral crystals in monzodiorite or as an essential mineral in veins and their reaction zones. At Kisladag, magmatic-hydrothermal brecciation associated with multiphase intrusions of latite porphyry is related to the Kisladag caldera. Tourmaline is an abundant and widespread alteration-induced mineral throughout the Kisladag porphyry system. Electron -m icroprobe analyses of the tourmaline crystals collected from both hydrothermal deposits show significant chemical variation within the range of buergerite compositions. The main substitution mechanism involves the CaFe2+[Na-1(Al,Fe3+)(-1)] exchange vector. Compositions deviate from ideal schorl-dravite along a trend that closely approximates the uvite exchange-vector. Mossbauer spectroscopy shows the presence of significant Fe3+ in all the tourmaline crystals, suggesting a high oxidation state for the ore-forming fluids, and for related hydrothermal systems associated with emplacement of subvolcanic intrusions.