Additional Details

Description

Mars Transverse Mercator (MTM) quadrangles –40252 and –40257 cover a portion of the highlands of Promethei Terra northeast of the Hellas basin (fig. 1). The map area consists of heavily cratered ancient highland materials of moderate to high relief, isolated knobs and massifs of rugged mountainous materials, extensive tracts of smooth and channeled plains, and other surficial deposits. Reull Vallis (fig. 2), an ~1,500-km-long outflow channel system, cuts through the southeast corner of the map area. Regional slopes are to the southwest, toward the Hellas basin, as indicated by martian topographic maps [U.S. Geological Survey, 1989; Smith and others, 1999] and the orientations of channels along the northeast rim of the Hellas basin. The martian highlands cover more than 60% of the planet's surface and are primarily in the southern hemisphere [Tanaka and others, 1992]. Most of the highlands consist of rugged, densely cratered terrains believed to represent the final phase of heavy bombardment in the inner solar system ~4.0 billion years ago [Murray and others, 1971; Schubert and others, 1992; Tanaka and others, 1992]. Parts of the martian highlands show evidence of extensive degradation and modification. The map area exhibits landforms created by numerous geologic processes, including tectonism, fluvial activity, and mass wasting. The occurrence of fluvial features, such as outflow channels and valley networks, has significant implications for past martian conditions. Determining the geology of the highlands northeast of the Hellas basin provides a better understanding of the role and timing of volatile-driven activity in the evolution of the highlands. Photogeologic mapping at 1:500,000 scale from analysis of Viking Orbiter images complements geomorphic studies of Reull Vallis and other highland outflow systems, of drainage networks, and of highland debris aprons and regional geologic mapping studies of the highlands at the 1:2,000,000 scale [Mest, 1998; Mest and Crown, 2001] and 1:1,000,000 scale [Mest and Crown, 2002]. Crater size-frequency distributions have been compiled to constrain the relative ages of geologic units and determine the timing and extents of the observed geologic processes.

Survey Date

2002

Print Date

2002

Languages

English