Reconnaissance geologic map of the Jizan Quadrangle, sheet 16/42 B, Kingdom of Saudi Arabia

Abstract

The Jizan quadrangle, bounded by lat 16°30’ and 17°00’ N. and long 42°30’ and 43°00’ E., is one of the southernmost quadrangles of the Kingdom of Saudi Arabia. It is named after Jizan, the largest city and principal port of the region, with about 30,000 inhabitants. Other significant towns and villages include Abu Arish, Al Madayah and Karbus, all linked to Jizan and adjoining quadrangles by paved roads. Most of the quadrangle is occupied by coastal plain bordering the Red Sea; one third is occupied by part of the Red Sea and the extreme northeast corner includes foothills of the Red Sea escarpment. The coastal plain, as much as 40 km wide, is covered by Quaternary surficial deposits overlying a sequence of Tertiary and Quaternary sedimentary rocks as much as 5 km thick. The only relief on the plain is provided by the Jizan salt dome, elevated about 50 m above sea level at Jizan city, and by small extinct volcanoes 100 to 150 m high near Abu Arish. The coastal plain is separated form islands, tidal mud flats and shallow lagoons. The sea is shallow, less than 200 m deep, and forms part of the shelf marginal to the main axial trough of the Red Sea. The high ground in the northeast of the quadrangle is formed by Jabal at Tirf, 452 m above sea level at its summit.