Geologic map of the Aeolis Quadrangle of Mars

Two principal physiographic provinces of Mars are represented in the Aeolis quadrangle: (1) Elysium Planitia in the north is part of a broad planet-encircling belt of relatively young lowland plains, and (2) cratered highlands in the south consist of roughly primitive terrain that extends to polar deposits around the southern ice cap (Condit and Soderblom, 1978: Scott and Carr, 1978). These two terrains are separated by an irregular discontinuous northwest-trending scarp that becomes less conspicuous and more segmented toward the east part of the map area. Two large channels transect the highlands; they widen northward downslope and have other features characteristic of terrestrial river beds. However, now fans or deltaic forms are visible at their mouths and their floors merge with the plains. One large shield volcano, Apollinaris Patera, projects above the plains adjacent to the highlands in the northeast part of the quadrangle. More than 4 km of relief occur across the region from the high plateau in the south and west, downslope northward to plains.