Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Petrogenesis of Alvand granitoidic mass

Authors
Mohammad Vali Valizadeh
Mahmoud Sadeghian
Faculty of Science, Tehran University, Tehran, Iran
Abstract
Alvand granitoidic mass is one of the Upper Cretaceous- Lower Paleocene emplacements age which intruded in Sanandaj- Sirjan metamorphic belt.
It crops out in an area between Hamadan and Tuyserkan cities with extension of 400 km This mass has been studied points of view by many investigators, but little attention has approximately its petrogenesis and tectonomagmatic origin. In this paper it is from different determine the relationship between the mode of occurrence and tectono- magmatic setting. The Alvand granitoidic mass may display a wide attempted to varieties of lithological composition, but it is mainly composed of tono- syenogranite and monzogranite. The geochemical analysis and Ab- Or- Qz diagram show that the range of pressure- temperature at the time of emplacement was 2 Kbar and 680-760 ⁰C.
The mineralogical, lithological, and geochemical studies along with field observations indicate that the Alvand granitoidic mass is of S type and palingenetic granitoidics.
Geochemical investigations reveals that the Alvand granitoidic mass is of syncollision origin [synorogenic (Laramide orogenic) to late orogenic].
The results of this study show that the Alvand granitoidic mass could be assained to orogenic granitoids and continental arc granitoids (CAG), resulting from Neotethys oceanic crust subduction beneath central Iran continental crust. The mass was emplaced in sanandaj- Sirjan metamorphic belt in upper Cretaceous- Lower Paleocene (about 65 my). Considering radiometric ages, it is concluded that magmatic cycle had been about 40 million years.
Keywords
Alvand granitoidic mass, Sanandaj-Sirjan

Subjects

 
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Scientific Quarterly Journal of Geosciences
Volume 5, Issue 19
Spring 1996, vol. 5, No. 19
Summer 1996
Pages 14-31