نوع مقاله : مقاله پژوهشی
نویسنده
دانشگاه آزاد اسلامی واحد خرم آباد
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
The Shaveli leucogranites, exposed north of Azna within the Sanandaj–Sirjan metamorphic-structural zone, contain important accessory minerals including garnet and tourmaline. This study aims to investigate the origin and crystallization conditions of these minerals based on petrographic and mineral-chemical analyses. Garnets are characterized by homogeneous compositions enriched in the spessartine component, and their textural and chemical features indicate a magmatic origin through direct crystallization from a felsic melt. Low CaO contents and Mn enrichment suggest crystallization within a peraluminous S-type magmatic system under low-pressure conditions in the upper crust. Tourmalines range compositionally from schorl to dravite and belong to the alkali-tourmaline group. Mineral-chemical data reveal two distinct tourmaline populations, representing magmatic and hydrothermal generations. The combined garnet and tourmaline chemistry indicates that the parental magma was derived from the partial melting of Al-rich metapelitic crustal materials and confirms the S-type affinity of the Shaveli leucogranites.
کلیدواژهها [English]
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