The investigation of mineral chemistry of garnet and tourmaline in Marziyan leucogranite (North Azna, Sanandaj-Sirjan Zone)

Garnet and tourmaline have been recognized as minor minerals in Marziyan leucogranites of the North of the Azna region as a part of the Sanandaj-Sirjan structural zone. These felsic rocks outcrop in metamorphic rocks such as micaschist and andalusite schist. Garnets are mostly anhedral to euhedral, without reaction rim as well as inclusion and they have uniform composition and rich in spessartine. Based on the petrographic and chemical studies, garnets have a magmatic origin and they are derived from a felsic melt because their CaO amount is <4wt%. Tourmalines are anhedral to subhedral, coarse to medium grains and they are classified in shorlite-dravite type as well as alkali group in composition. Tourmalines are categorized into two groups of magmatic with a ratio higher than Al, Fe/Fe+Mg and hydrothermal with a low Fe#. Mineral chemistry of garnet and tourmaline minerals signifies the S-type Marziyan granite magma.