Journal of Petroleum Geology, Vol.9, No.2, pp. 195-206, 1986

©Copyright 2000 Scientific Press, Ltd.

LITHO- AND MICROFACIES OF UPPER JURASSIC CARBONATE ROCKS OUTCROPPING IN CENTRAL SAUDI ARABIA

Saleh M. Okla*

* Geology Dept., King Saud University, PO Box 2455 Riyadh 11451, Saudi Arabia.

Abstract

A study of surface sections of Upper Jurassic rock units near the city of Riyadh has revealed a total thickness of 500 m. These rock units are the Tuwaiq Mountain Limestone, Hanifa Formation, Jubaila Limestone, Arab Formation and Hith Anhydrite. The characteristic microfacies of Tuwaiq Mountain Limestone include spicular biomicrites in the lower part of the formation, and corals, stromatoporoids and algal biomicrites in the upper part. The characteristic microfacies of the Hanifa, Jubaila and Arab Formations include spicular biomicrites with some argillaceous shales alternating with pelsparities and oosparites. Conglomeratic micrites, dolomites and breccia are found in the upper Jubaila Limestone and the Arab Formation.