Application of space imagery in Algerian Sahara

Grand Erg Oriental of the Algerian Sahara is one of the most difficult terrain having high altitude dunes ranging in height from 100 m to 300 m above ground level and 250 m to 530m above M.S.L. Interpretation of space Imagery for morphotectonic features like structures and lineaments over such a rough terrain had been an enigma. For the first time in 1978 an attempt was made in connection with exploration for hydrocarbons. A new approach on the hypothesis that the configuration of dunes is directly related to the subsurface topography which in turn being the product of geology and tectonics has been developed and the results obtained had been encouraging. The study resulted in delineating of more than 200 structures and 700 lineaments. Many of these have since been confirmed by geophysical survey and subsequent drilling. It is observed that the deep seated structures are more prone to interpretation on Landsat frames, in areas covered by high dunes as compared to lineaments. Contact of dune types, identified, may reflect variation in subsurface geology.