Grand Erg Oriental small but ancient settlement of Ghadames at the Libyan frontier. Another and better road from Hassi Messaoud goes south, also crossing the grand erg where it passes a well called "Hassi Tartrat", before reaching the erg's far side. Further south lies the Ahaggar mountains. The cities of Wargla and Touggourt lie outside the western limits of the erg. Nearby, within the accepted boundaries of the "Grand Erg Oriental", the landscape is described as being "practically free from [sand] dunes" evidently due to strong, persistent winds. Petroleum and other hydrocarbons have been extracted in Algeria, from areas in and surrounding the
Issaouane Erg which can take hundreds of thousands of years to form; mesoscale dunes (including the stardunes), which form on the mega dunes; and yet smaller ones which migrate over the bigger ones. In the NASA images, the light-blue spots in the valleys between the dunes (which are red from iron oxide) are "sabkhah", or salt flats, left after the evaporation of accumulated water. Neolithic artifacts, sculptures and paintings have been found in the Issouane Erg. from the Kiffian culture. The Issaouane Erg contains oil; the Tifernine oilfield is explored by the Algerian state oil company Sonatrach, which began developing the oilfield