کانی شناسی و بلورشیمی لامپروفیرهای شمال غرب ایران

There are numerous outcrops of lamprophyric rocks, as sill and dikes, in the northwestern part of Iran. These rocks can be classified in two mica- and amphibole-rich types. Amphibole-rich type includes amphibole, olivine psudomorphs, and clinopyroxene phenocrysts in the matrix of feldspar and altered glass. Mica-rich lamprophyres include mica and clinopyroxene phenocrysts in the matrix of feldspar and glass. Amphiboles represent kaersutite composition and mica crystals mainly show phlogopitic composition. Clinopyroxene crystals have mainly salite-diopside composition. Clinopyroxenes in the amphibole-rich type have higher Al2O3 content. Studied lamprophyres are formed in a high oxygen fugacity condition and their magmas have been experienced low pressure crystallization. According to nature of minerals, mica-rich lamprophyres have calc alkaline nature and are minette and amphibole –rich type represents alkaline nature and can be consider as comptonite. Mica-rich lamprophyres originated from phlogopite and/or potassic amphibole bearing metasomatized lithospheric mantle in a orogenic tectonic setting. Amphibole-rich lamprophyres probably originated from a lherzolite mantle that includes fluid-bearing minerals.