Origin of Antecrysts in Igneous Rocks from the Salavat Range (NW Iran): an Explanation for the Geochemical Signature of Potassic Alkaline Rocks

Abstract Abundant silica-undersaturated potassic lavas are found in the centre of Turkish–Iranian plateau (NW Iran) as flows, pillows and dykes. They display abundant zoned clinopyroxene macrocrysts xenoliths igneous cumulates. We determined four types crystals (Type-I, -II, -III -IV) on basis their composition zoning patterns. Use situ compositional data, together with whole-rock major trace elements isotopic signatures host provided evidence for derivation different clinopyroxenes from at least two contrasting parental melts. Our findings consistent an origin ultrapotassic sodic alkaline melts deep-seated compaction pockets inferred our previous studies magmatism throughout plateau. The melt, which accumulated top pockets, eventually ponded close to spinel–garnet mantle transition generated colourless antecrysts (Type-I Type-II) clinopyroxenite When pocket impinged continental lithosphere, interstitial segregated flowed inside dykes where grass green (Type-III) phenocrysts (Type-IVa) crystallized a melt having geochemical signature melt. Later, crustal level, crystallization processes produced Type-IVb phenocrysts. results odds paradigm magmas NW Iran being derived strictly single source.