During Cambrian clastics and carbonates were deposited in two sedimentary cycles in the Oman Mountains and Haushi-Huqf. At approximately the same time a thick sequence of salt and other evaporites was formed in the desert plains.
Continental sedimentation occurred in the Cambro-Ordovician near the Haushi-Huqf, passing westwards and northwards to shallow marine depositions (Ghaba). Thereafter erosion and non-deposition prevailed until Permian transgression initiated an almost continuous period of carbonate sedimentation lasting until end Cenomanian.
Lower and Middle Cretaceous carbonates of the Thamama and Wasia Group provide the oil in Yibal, Fahud and Natih.
There was a break of sedimentation from Turonian to Lower Santonian. During Campanian a geosyncline in the Oman Mountains was formed and flyschtype Sediments with exotic blocks were deposited.
Ultrabasic material (ophiolites) extruded, probably along tension faults in the Gulf of Oman, and was deposited in the geosyncline.
Consequent upon the infilling of the geosyncline a compressional tectonic phase elevated the region of the Oman Mountains. Thereafter a succession of Tertiary marine transgression followed in Palaeocene, Oligocene and Miocene.
Strong orogenetic movements occurred prior to Permian transgression and in Upper Cretaceous. Palaeozoic evaporites caused salt tectonics. Severe Tertiary movements took place also in late Oligocene-early Miocene.
The paper presents a concise description of the General Geology of Oman. Basic geological data were obtained from exploration wells and from geological and geophysical field work. The geological results and conclusions are compiled from numerous P.D.(O) reports. The extent of the area discussed is shown on Fig. 1. The author's contribution is that of compiling and elucidating results.
Since our geological knowledge of Oman is still rather limited, only a tentative geological history is presented. During the next winter season (1966/67) additional geological field work will be undertaken in the Oman Mountains and as a result our present geological concepts may have to be altered.
As early as 1924/25 geologists made reconnaissance trips along the Batinah Coast and in the Jebe1 Akhdar of Oman. In 1938/39 the coastal areas of Oman were again visited. During the years 1948/52 several geological expeditions were carried out, but progress was hampered because of difficult access and tribal conditions. Only in 1954 was a detailed geological mapping by R. H. TSCHOPP Petroleum Development (Oman) Ltd. 16-11 I of surface structures in the desert west of the Oman Mountains undertaken.
Geological field observations were mainly made in the Oman Mountains and its foothills, and in the Haushi-Huqf area. The geological mapping was facilitated by air photographs which cover almost the entire country of Oman. Geological parties spent a total of 65 party months in the fi
