Tuwaiq Mountains Formation

The Tuwaiq Mountains Formation, located on the western and southwestern sides of al-Rub' al-Khali (Empty Quarter) Desert in the Kingdom of Saudi Arabia, is made from limestone. It is considered one of the important geological formations with visible outcrops, representing the oldest formation in the Empty Quarter Desert.

In general, the Empty Quarter Desert is the largest continuous desert in the world, covering an area of about 550,000 km². It was formed in a wide, low-lying area during the dry periods of the Tertiary and Quaternary geological epochs. This desert is still expanding due to severe desertification factors, along with sand movement and drought.

As a result of the vast area covered by the Empty Quarter Desert and its continuity, outcrops of geological formations are almost non-existent, except in some areas, including the edges of Tuwaiq Mountains. Most of the formations have been found in the middle of the Empty Quarter Desert and its edges during survey operations conducted by Saudi Aramco for gas and oil exploration in the Empty Quarter.

The Tuwaiq Mountains Formation is situated on the western and southwestern sides of the Empty Quarter Desert. It extends from Wadi al-Helo in the north, through the Bani Hatmah highlands, then al-Munbatih and Ajhaymin, reaching Jabal Huwayman, which is located in the south and represents the last outcrop, after which this formation is submerged under the sands.

Formed from limestone, the Tuwaiq Mountain Formation dates back to the early Upper Jurassic epoch, one of the geological periods. It is considered one of the geological formations with visible outcrops in the Empty Quarter Desert and the oldest among them. East of this formation, the sands of the Empty Quarter extend in the form of longitudinal dunes, separated by gravel-covered plains.