نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه زمین شناسی معدنی و آب، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران
2 گروه زمینشناسی ،دانشکده علوم زمین، دانشگاه تحصیلات تکمیلی علوم پایه زنجان، زنجان، ایران
3 گروه زمین شناسی معدنی و آب، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران.
4 گروه زمین شناسی، دانشکده علوم زمین، دانشگاه شهید چمران اهواز، اهواز، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Dalampar ophiolite mélange is an uncharacterized segment of the Neotethys ophiolite, situated between the Sardasht and Selmas ophiolites northeast of Oshnavieh city, at the end part of the Sanandaj-Sirjan metamorphic belt. The main rock types in the area include serpentinized peridotites, pillow basalts, various gabbros, pelagic limestone, radiolarite, and volcano-sedimentary units. Gabbros can be classified into two types: coarse-grained with a pegmatitic texture, and fine-grained gabbros occurring as masses and dikes. They primarily consist of plagioclase (50–60% by volume) and clinopyroxene (20–30% by volume). Secondary minerals in these rocks include sericite, chlorite, calcite, tremolite-actinolite, and epidote. According to mineral chemistry investigations, the compositions of clinopyroxene, amphibole, and plagioclase minerals range from diopside to augite, magnesiohornblende, and oligoclase to labradorite, respectively. According to geothermometric calculations, clinopyroxenes formed at pressures of 5 to 10 kbar, temperatures between 900 and 1200 °C, and under conditions of high oxygen fugacity. The chemical compositions of clinopyroxene and amphibole indicate that these minerals crystallized from a sub-alkaline magma typical of island arc tholeiites (IAT) and boninites found in subduction zones.
کلیدواژهها [English]
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