Erg (landform) when liquid methane rained and eroded the ice bedrock, possibly in the form of flash floods. Alternatively, the sand could also have come from organic solids produced by photochemical reactions in Titan's atmosphere. Erg (landform) An erg (also sand sea or dune sea, or sand sheet if it lacks dunes) is a broad, flat area of desert covered with wind-swept sand with little or no vegetative cover. The term takes its name from the Arabic word "ʿarq" (), meaning "dune field". Strictly speaking, an erg is defined as a desert area that contains more than of aeolian or wind-blown sand
Grand Erg Oriental "Grand Erg Oriental". In addition to oil in Wargla and Hassi Messaoud (see above), other Algerian hydrocarbon sites include In Salah, a city (pop: 44,000) to the erg's southwest, yielding natural gas, and also El Adeb Larache, Edjelé, Tingentourine, and Zarzaïtine (south of the erg, close to Libya). One of Algeria's largest field of natural gas is near Ghardaïa, west of Touggourt. Gas pipelines have been constructed north to the Mediterranean port of Bourgie, and later northeast through Tunisia. Along the north rim of the "Grand Erg Oriental", both the physical ecology and the human culture surviving there since ancient