The Empty Quarter : saudi arabia
"Jebel Tuwaiq is a narrow escarpment (center) that cuts through the plateau of Nejd in central Arabia, running approximately 800 km from the southern border of Al-Qasim in the North, to the Empty Quarter desert near Wadi ad-Dawasir in the South.
It is 600 meters high with a Middle Jurassic stratigraphic section. The eastern side slopes downwards gradually, while the western side ends in an abrupt manner. The escarpment can be thought of as a narrow plateau.
Many narrow valleys (wadis) run along its sides, such as Wadi Hanifa, and a group of towns lie on its central section, including the Saudi capital, Riyadh. Many settlements have historically existed on either side of it as well, such as those of Sudair and Al-Washm. The Tweig escarpment is mentioned in Yaqut's 13th century geographical encyclopedia under the name Al-'Aridh, though for the past few centuries that name has applied only to the central section of it, around Riyadh.
The Rub' al Khali "Empty Quarter" (right) is the largest contiguous sand desert (erg) in the world, encompassing most of the southern third of the Arabian Peninsula. The desert covers some 650,000 square km (250,000 sq mi) and is part of the larger Arabian Desert.
The terrain is covered with sand dunes with heights up to 250 meters (820 ft), interspersed with gravel and gypsum plains. The sand is of a reddish-orange color due to the presence of feldspar.
Along the middle length of the desert there are a number of raised, hardened areas of calcium carbonate, gypsum, marl, or clay that were once the site of shallow lakes formed as a result of "cataclysmic rainfall" similar to present-day monsoon rains. Lakes in the southwest of the Rub' al Khali show evidence of lasting up to 800 years, due to increased runoff from the Tuwaiq Escarpment.
- Geo-Historical Text : Wikipedia
- Calculations : WolframAlpha Pro
- Satellite Imagery: ESRI ArcGIS
Overlay Source Image: NASA Johnson