Geochemistry and mineral composition of lamprophyre dikes, central Iran: implications for petrogenesis and mantle evolution

Late Proterozoic–Early Cambrian magmatic rocks that range in composition from mafic to felsic have intruded into the Hour region of the central Iranian micro-continent. The Hour lamprophyres are alkaline, being characterized by low contents of SiO_2 and high TiO_2 , Mg# values, high contents of compatible elements, and are enriched in LREE and LILE but depleted in HFSE. Mineral chemistry studies reveal that the lamprophyres formed within a temperature range of ∼ 1200 ^∘ to 1300^∘C and relatively moderate pressure in subvolcanic levels. The Hour lamprophyres have experienced weak fractional crystallization and insignificant crustal contamination with more primitive mantle signatures. They were derived from low degree partial melting (1–5