Geochemical investigation on granitoied pluton of Chah Salar, in centeral Iran structural Zone, Nishabour, north-east of Iran

Category Petrology
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Zohreh, Farsi; Mahmood, Sadeghian; Alireza, Khanalizadeh; Habibollah, Ghasemi
Holding Date 20 September 2008

The Studies area is located in 55 km of SW Nishabour and in the N-NE of Chah Salar village of Khorasan Razavi province.
Based on the field observations, petrography and geochemical classification, this pluton include an approximately compositional range from diorite, quartz-diorite Granodiorite and granite. Granular, myrmekitic and graphic textures have been seen in these rocks. Results of this research indicate the studies pluton is post- Eocen in age. Variation diagrams of major and trace elements indicate that these rocks have a continuous compositional spectrum and they are formed from differentiation of a basic magma. Also, the pattern of variation trends in the compatible and incompatible diagrams versus each other show that this compositional continuity resulted of fractional crystallization.Further studies using spider diagrams showed that all of the samples enriched in LIEE and incompatible elements. Lower anomalous of Ti and Nb indicates that parent magma contaminated with crustal lithosphere.
According to petrographical and geochemical evidences such as absence of muscovite and index minerals of metamorphic rocks, abundance of apatite and sphene, 57-75% SiO2 content, low Ti content the studied granitoidic rocks are I-type granitoids.
Different tectonic diagrams, granitoids of area are VAG , Syn-COLG type. Geochemical characteristics indicate that Chah-Salar pluton have calc-alkaline and metaluminous. Detailed investigations of field geology, Petrography and geochemical characteristics indicate the magma that formed this pluton is resulted from partial melting of subducted Oceanic slab with amphibolitic composition, and then evolved by fraction crystallization and magma contamination.
Key Words: Petrology, Geochemistry, Gabbrodiorite, Chahsalar, Nishabour