نوع مقاله : علمی -پژوهشی
نویسندگان
1 گروه زمین شناسی، واحد اهواز، دانشگاه آزاد اسلامی، اهواز، ایران
2 گروه زمین شناسی، دانشکده علوم زمین، دانشگاه شهیدچمران اهواز، اهواز، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسنده [English]
Baba-Ali and Galali deposits are located in 30 and 60 km northwest of Hamedan in northwest part of the Sanandaj-Sirjan zone. The host rocks of these deposits are metavolcano-sedimentary successions of Songhor series in Permo-Triassic age. Stratigraphic position of ore horizons, geometry of orebodies, ore structures and textures in different scales and paragenetic sequence of minerals all show close genetic relation between iron ore and the metavolcanosedimentary and subvolcanic rocks. The host rocks in the area are felsic to intermediate metavolcanic rocks, more than lava and rhyolitic tuffs with interculations of carbonate and metatuff-sandstones. Field observations and petrography show that emplacement of plutons and subvolcanic rock units with composition of gabbrodiorite, quartzmonzodiorite, granodiorite, syenite, syenogranite and granite in these successions caused deformation and metamorphism of ore and country rocks. Fluid inclusion studies within the quartz crystals indicate that main salinity varies between 12±5 and 9±5 wt.% NaCl in Baba-Ali and Galali deposits respectively. Homogenization temperature for Baba-Ali and Galali deposits are 226±5 and 220±5 oC respectively. Occurrence of dynamothermal regional metamorphism in these deposits typically involves a lengthy period of time, during which there was a tendency toward isotopic homogenization specifically in O and H stable isotopes and show the role of metamorphic waters in mineralization process. Measurement of δ34S (CDT) in first generation of pyrite is higher than another ones, so these data confirm the volcano-sedimentary origin of primary iron mineralization.
کلیدواژهها [English]
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