Minralogy and geochemical characteristics of nabijan intrusion (Southwest of kaleybar)

Category Petrology
Group GSI.IR
Location 23th symposium on geosciences
Holding Date 05 May 2008

      Nabijan intrusion, which located in the southwest of kaleybar has been injected into upper cretaceous limestone and volcanic rocks and associated with the formation of garnet and epidote minerals. According to petrographic and geochemical studies, these rocks are gabbro and diorite that gabbro rocks indicate characteristics of tholeitic and diorite rocks indicate calc-alkaline magmatic series. Low content of incompatible elements include K, Rb, Ba, Th and high content of compatible elements such as Ni, Co, Cr, V relatively in the gabbros can be related to mantle origin of mafic magma, meanwhile the content of compatible element can not be display characters of parental mafic magma. Less content of the compatible elements in compare to parental mafic magmas result from differentiation of olivine, pyroxene and amphibole and magnetite minerals. High content of LREE like La, Ce and Nd relative to HREE such as Sm, Yb and Y, Nb suggested for either mantle enrichment or contamination of mafic magma with crustal materials. There is no gradually trend in gabbroic and dioritic samples in Harker diagrams with the increasing of SiO2 content that we cannot consider the probability of the formation of diorite from differentiation of mafic magma and be considered as a result of assimilation of crustal rocks which are associated with enhancement of incompatible elements such as Ba, K, Rb and biotites of two generation of dioritic rocks.