Libyan Desert

The Libyan Desert, which covers much of eastern Libya, is one of the most arid places on earth. In places, decades may pass without rain, and even in the highlands rainfall happens erratically, once every 5--10 years. At Uweinat, the last recorded rainfall was in September 1998. There is a large depression, the Qattara Depression, just to the south of the northernmost scarp, with Siwa oasis at its western extremity. The depression continues in a shallower form west, to the oases of Jaghbub and Jalo. Likewise, the temperature in the Libyan desert can be extreme; in 1922, the town of Al 'Aziziyah, which is located west of Tripoli, recorded an air temperature of 57.8 °C (136.0 °F), generally accepted as the highest recorded naturally occurring air temperature reached on Earth. There are a few scattered uninhabited small oases, usually linked to the major depressions, where water can be found by digging to a few feet in depth. In the west there is a widely dispersed group of oases in unconnected shallow depressions, the Kufra group, consisting of Tazerbo, Rebianae and Kufra. Aside from the scarps, the general flatness is only interrupted by a series of plateaus and massifs near the centre of the Libyan Desert, around the convergence of the Egyptian-Sudanese-Libyan Borders. Slightly further to the south are the massifs of Arkenu, Uweinat and Kissu. These granite mountains are very ancient, having formed much before the sandstones surrounding them. Arkenu and Western Uweinat are ring complexes very similar to those in the Aïr Mountains. Eastern Uweinat (the highest point in the Libyan Desert) is a raised sandstone plateau adjacent to the granite part further west. The plain to the north of Uweinat is dotted with eroded volcanic features. With the discovery of oil in the 1950s also came the discovery of a massive aquifer underneath much of the country. The water in this aquifer pre-dates the last ice ages and the Sahara desert itself. The country is also home to the Arkenu craters, double impact craters found in the desert.