نوع مقاله : مقاله پژوهشی
نویسندگان
1 میدان هفت تیر دانشگاه صنعتی شاهرود
2 شاهرود- بلوار دانشگاه- دانشگاه صنعتی شاهرود- دانشکده علوم زمین
3 پژوهشگر وابسته، دپارتمان علوم زمین، دانشگاه پیزا، ایتالیا
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The granitoid bodies of the Sarbijan–Dalfard district within the Jebal-e-Barez mountain range form part of the Oligocene–Miocene magmatism of the southeastern part of Urumiyeh–Dokhtar magmatic belt. These intrusions consist of diorite, monzodiorite, granodiorite and granite and display predominantly anhedral to subhedral granular textures. Biotite, as the main mafic mineral in most of these bodies, has a primary magmatic origin and a magnesium-rich composition. Thermometry based on Ti-in-biotite indicates closure temperatures of 600–730 °C for this mineral, consistent with crystallization and replacement conditions of calc-alkaline granitoid magmas. Barometry based on total Al in biotite indicates emplacement of these intrusive bodies at pressures of 1–2.5 kbar, corresponding to shallow upper crustal depths (approximately 3–7 km). Oxygen fugacity and the coexistence of Mg-rich biotite with iron-oxide phases imply oxidizing conditions and affiliation of these granitoids to the magnetite series with copper mineralization potential. Field, petrographic and mineral chemistry evidence collectively indicate that the granitoid bodies of the Sarbijan–Dalfard district were derived from a calc-alkaline, metaluminous, I-type granitoid magma in a magmatic-arc environment contemporaneous with subduction-related collision during the Oligocene–Miocene. These results are consistent with the obtained founding’s from proposed models for arc magmatism in the southern part of the Urumiyeh–Dokhtar magmatic belt.
کلیدواژهها [English]
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