Writers : Atarpour, H and Aftabi.A
Refference : Geosciences Scientific Quarterly Journal,No.:15-16,P.:36
Publishing Year : 1374

Abstract :
The shoshonitic associations in Iran are limited to volcanic belts of Eocene to recent volcanism.
Shoshonitic eruptions are reported in Uromieh- Dokhtar volcanic belt, Azerbaijan, Alborz, Sabzevar, Lut Block and Eastern zones of Iran as mat ic to felsic volcanic rocks.
Geological considerations show that shoshonitic rocks are erupted and exposed in Azerbaijan province (Mianeh, Saray, Sahand, Sabalan, Takab, Qorveh), Alborz zone (Taleghan- Alemut, Damavand) and Uromieh Dokhtar (Qom- Aran, Saveh, Natanz- Nain, Shahr- Babak, Bardsir).
Petrographic aspects of shoshonitic rocks correspond with typical shoshonitic rocks of many petrological provinces of the world. However the Iranian absarokites have plagioclase phenocrysts. Mineralogically, the shoshonitic suites of Iranian volcanic belt are mainly composed of divine, clinopyroxene, labradorite, sanidine, analcime and zeolites. Minor minerals are magnetite, apatite and hematite.
Geochemistry of the major, minor and trace element show that these rocks have geochemical aspects
of other shoshonitic rocks.
Geochemically, P, K Ba, Rb, Sr, Zr show positive anomally, whereas Ti and Nb strongly show negative orofile.
It is possible that petrogenesis of shoshonitic magmas in Iranian volcanic belt is probably related to melting of metasomatized upper mantle or lower crust (Oceanic Crust). Differentiation, assimilation and mixing may have been important for evolution of shoshonitic magmas. These, however need further isotopic studies to be proved and also to propose a geodynamic model.
Subject List : shoshonite