Petrochemical Investigation On El Ehena Pluton, Western Al-Quwayiyah Region, Saudi Arabia

Abstract

The El Ehena area represents a small circular granite intrusion intruded in a metasedimentary sequence. The rocks are coarse grained with hypidomorphic texture and consist mainly of quartz, K-feldspar mostly perthitic and sodic plagioclase. They are identified as syenogranite and monzogranite. Geochemical characteristics of the granitic rocks document alkaline affinity. They are peralumi-nous in nature. All available data suggest that El Ehena pluton belongs to I type granite. The most likely model for the evolution of the granite is from volcanic arc magma, and represents transitional tectonic environment formed during the initial stage of back-arc spreading near continental area.