ANALOGS OF MARTIAN EOLIAN FEATURES IN THE WESTERN DESERT OF EGYPT TED A. MAXWELL and FAROUK EL-BAZ National Air and Space btuseum

Darlit streamlined streaks observed in orbital images of the Western Desert of Egypt are similar in saale and form to craterand knob-related streaks on the martian surfaae. In Egypt, dark streaks form in the lee of topographic highs^ ranging in sise from small hills a few meters across^ to the 60 km wide Uweinat massifs On the surfaae of Mars, streaks may he either lighter or darker in tone than the surrounding plains. Individual streaks occur primarily in the lee of craters, although in the Cerberus region, several tighttoned streaks occur in the lee of irregular knobs, similar to those in southwestern Egypt. Knoband crater-related wind streaks en both Earth and Mars owe their aharacteristic patterns to the local deviation of wirvd around topographic harriers. Knob streaks on hath planets most often display a convergent pattern, whereas crater streaks cm, Mars are more often divergent. Field investigation in southwestern Egypt indicates that the aharacteristic shape of wind streaks is a function of the transport and deposition of material surrounding the streak rather than erosion or deposition in the lee of the obstacle. In addition to these landform analogies visible at orbital altitudes, many near-surface features in the Western Desert are similar to those seen in Viking lander images from the surface of Chryse Planitia on Mars, Sand drifts and small dunes are -present in both deserts, as are pitted and faceted rocks that occur in both non-vesicular basalt and in sandstones, Evidence of wind pitting and erosion in the Western Desert suggests that rocks in the Viking 1 landing site nay not necessarily consist of vesicular basait, but may owe their surfiaial features to wind erosion.