Mineralogy Of The Marrat Clay Deposits, Riyadh Region, Central Saudi Arabia

Abstract

Clays in the Marrat Formation, which crop out 200 km west of Riyadh, Saudi Arabia, are dominantly composed of brownish red to dark red mudstones and shales. Marrat clays are chiefly composed of kaolinite and lesser amounts of illite. Quartz is the major non-clay mineral. The red colour of the clay is due to hematite present in very small amounts in the samples. The clays were probably formed by partial laterization of acid igneous rocks in the west of the study area. The products were transported to the present area and deposited in a shallow marine environment during early Jurassic in the Toarcian times.