GEOCHEMISTRY AND PETROGENESIS OF PLUTONIC MASSES IN NORTH OF SONQOR (WEST OF IRAN)

Resumo

The study area is a quadrilateral that is in west of Iran and north of Sonqor city of Kermanshah province. This area is 155 km2 between eastern longitude 47˚ and 40 ′ to 47˚ and 52 ′ and northern latitudes 35˚ and 00 ′ to 35˚ and 04 ′. In this range, the intrusive rocks are Olivine gabbro, gabbro, gabbro diorite, diorite, monzonite, alkaline sinite, quartz diorite, quartz monzodiorite, quartz monzonite, quartz alkaline sinite, tonalite, granodiorite, granite and alkaline granite, they were injected in the iron ores of cretaceous which has resulted in contact metamorphism and created hornfels at the site of contact. After comprehensive sampling of all required igneous rocks and according to the thesis objectives, 90 thin sections were prepared and after petrography, 24 samples were selected for geochemical experiments. XRF analysis were performed on 9 samples and ICP and alkaline fusion were performed on 15 samples. According to geochemical and petrological studies, the magmas forming these intrusive igneous rocks are from one region and because of magmatic differentiation or fractional crystallization, they from basaltic to acidic terms. According to the alkaline-silica diagrams, the studied rocks are in the range of tolite, calk-alkaline, potassium-rich calk-alkaline, and shoshonitic series. Based on tectono-magmatic diagrams, samples of this quadrilateral have a meta-alumina nature and granitoids are in the range of arc islands granites, continental arc granitoids and continental collision granitoids. The mineralogical and chemical composition of the acidic rocks in the area show that the granites in this study are type I.