Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Petrology and geochemistry of the intrusive bodies south of Bostan Abad

Authors
Mohammad Vali Valizadeh
Babak Mostofizadeh
Department of Geology, Faculty of Science, Tehran University, Tehran, Iran
Abstract
In a region northwest of Iran, (Bostan Abad, Eastern Azarbaijan) there are intrusive bodies with Eocene-Oligocence age, that have overall northwest-southeast trend. The rocks of these bodies fall within the range of medium to acidic, that have intruded the Eocene volcanic series and constituting contact metamorphic aureole of low grade Moreover, having the same features as albite - epidote hornfels facies. These rocks compositionally belong to the calc-alkaline and based on computer-criteria, in the orogenic belt, follows the tectonical regime of the VAG. Considering changes in the abundance of minerals such as pyroxene, magnetite, amphibole, biotite, plagioclase and alkali feldspar in the intrusive rocks, hence, it is indicative of successive process of differentiation in intermediate magma, and ultimately creating variation in lithology.
The studies shows that water vapour pressure for the formation of igneous bodies has been 0.2-2 kbar- and with regards to conditions produced contact facies and textural characteristics; it seems that magmas after formation and ascent reaches the epizonal level of the crust. In other words, these magmas have been emplaced in the subvolcanic conditions. The latter, more or less have undergone contaminations with crust, up to their emplacement. By considering trace elements, distribution patterns; the common character of VAG for the intrusive bodies, ultimately introduces the CAG Setting.
Keywords
intrusive bodies, Bostan Abad

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 7, 25-26
Autumn & Winter 1998, vol. 7, No. 25-26
Winter 1998
Pages 26-37