Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Geographical, petrological and geochemical characteristics of the shoshonitic rocks in Iran

Document Type : Original Research Paper

Authors
Habibeh Atapour 1
Alijan Aftabi 2
1 Geological Survey of Iran, Kerman Centre
2 Shahid Bahonar University, Geology Department, Kerman
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 mafic 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 olivine, 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 anomaly, whereas Ti and Nb strongly show negative profile.
     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.
Keywords
Geochemistry
Shoshonitic Rocks
Subjects
 
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Scientific Quarterly Journal of Geosciences
Volume 4, 15-16
Spring & Summer 1995, Vol. 4,No. 15-16
Summer 1995
Pages 36-49