Data

Mars presents two different terrains, a highly cratered surface that lies mostly in the southern hemisphere and sparsely cratered plains that lie mostly in the northern hemisphere. The cause of the dichotomy is a still unsolved fundamental problem of Martian geology, analogous to the problem of continents and ocean basins in terrestrial geology. The present features of the plains in...

The Macrobius quadrangle is in the northeast quadrant of the Moon's near side. Although predominantly a highland area centered around the Taurus Mountains (Montes Taurus), it is bounded by three major mare-filled basins: Tranquillitatis, the oldest, to the south; Serenitatis to the west; and Crisium on the east. Most of the geologic units within the quadrangle have been profoundly...

The Mare Boreum geologic map portrays the north polar are of Mars above lat 65 degrees N. The area contains five physiographic provinces: (1) a residual ice cap characterized by troughs with a counterclockwise outward spiral pattern (Mariner 9 frames DAS 13317550 and DAS 13353320); (2) layered terrain adjacent to the ice cap, exposed within the spiral troughs; (3) a circumpolar band of...

The Mare Tyrrhenum quadrangle is bounded by lat 0 degrees and 30 degrees S. and long 225 degrees W. and 270 degrees W. The central part of the quadrangle is dominated by Tyrrhena Patera, a large shield volcano, and associated low-albedo ridged plains that probably are basaltic lava flows similar to the lunar maria. The western, northern, and eastern margins of the quadrangle are located...

The map area contains two mare provinces, one terra province, and one province of mixed mare and terra. The maria are the semicircular southern half of Mare Crisium and the northeast sector of Mare Fecunditatis. The massive belt of terra that arcs across the quadrangle between these maria is the south rim of the Crisium multiringed basin; its southwest part is probably superposed on an...

The Margaritifer Sinus quadrangle lies within a broad north-sloping trough, the Chryse lowland, between the elevated Tharsis plateau to the west and the cratered upland to the east. The rugged, uniquely martian chaotic terrain is best developed in this quadrangle. Sinuous furrows a few kilometers wide and as much as several hundred kilometers long cover most of the quadrangle; in several...