Ordovician rocks in the Oman mountains: the Amdeh formation

Abstract

Recent work in the Saih Hatat region of the Oman Mountains has established an early Ordovician age for the Amdeh Formation. This dating is based on assemblages of brachiopods, trilobites, and lamellibranchs together with microflora and trace fossils from several localities. The formation comprises a sequence of shallow marine clastic rocks at least 3400 m thick which has been measured in detail in Wadi Kahza, some 40 km southwest of Muscat. The sequence may be divided into five members and a preliminary account of the stratigraphy is given, accompanied by illustrations of some of the characteristic sedimentary structures, macrofauna, and trace fossils. The Amdeh Formation is a marine equivalent of the continental to shallow marine sediments of interior Oman and the Saq and Tabuk Formations of Saudi Arabia and southwest Jordan. It has apparently been subjected to Late Paleozoic orogenic movements tentatively related to the Hercynian Orogeny