Gillman, Michel (Auxerap Jeddah)
Geological and above all geophysical surveys, followed by the deep well of Mansiyah, have permitted a better knowledge of the structure of the coastal plain of Jizan stretching along the foot of the Asir high granitic or metamorphic mountains in the south western part of Saudi Arabia. This elongated plain belongs to the eastern edge of the Red Sea wide graben formed by tension and limited with a faulty, volcanic zone. It is only in the eastern limit of the Jizan Plan that the Secondary and Tertiary sedimentary series outcrop; that is to say, the Khums sandstone and the Hanifa limestone from the ante-Jurassic to Upper Jurassic time which were deposited on the southern margin of the Arabo-Nubian shield and were covered with the Upper Tertiary Baid formation in angular disconformity.
The Baid formation corresponds to the marginal deposits of the Red Sea graben, basinwards the Mansiyah well No. 1 penetrated a thick continental series, then a massive salt penetrated a thick continental series, then a massive salt sequence and finally marine clastic deposits.