Data Releases

The map area, in the Coprates 1:2,000,000-scale quadrangle MC-18 NW lies in the heart of the Valles Marineris trough system. The western part of Ophir Planum (36,660 km2) occupies 40 percent of the map areas; parts of Candor, Melas, and Coprates Chasmata make up the remainder. The troughs contain distinctive landslide deposits, normal faults, possible young volcanic rocks, and layered...

The Wilhelm quadrangle lies along a mare highlands boundary west of the crater Tycho, southeast of Mare Humorum, and southwest of Mare Numbium. The outer scarp of the Orientale basin is 1200 km to the West-Northwest. The quadrangle is characterized by pitted and mantled appearing terra, which in the north is interrupted by patches of mare and in the south by several large pre-Imbrian...

Olympus Mons is the largest known volcanic construct in the Solar System; it is more than 600 km across and more than 27 km above datum. The volcano and the great scarp that bounds it have been the subject of much scientific controversy. Although it has been possible to generate an empirical model that closely resembles Olympus Mons, the dynamics of scarp formation are still unproven...

The east Mangala Valles area merits detailed geologic study because it contains several small channels whose ages can be determined relative to geologic units that range in age from early (Noachian) to late (Amazonian) periods of Martian history. Because small channels are of three ages and geomorphic types, their study increases our understanding of the continuity of fluvial processes...

The Galindo quadrangle (V-40; centered at lat 12.5 degrees S., long 255 degrees) was geologically mapped at 1:5,000,000 scale under the Venus Data Analysis and Venus Geologic Mapping Programs as part of a project focused on the study of venusian geologic terrains containing assemblages of coronae, arachnoids, and novae; these are enigmatic circular features perhaps related to hot-spot...

Since the 1970's, when the Mariner 9 spacecraft revealed the geologic diversity of Mars, the Chryse Planitia region has been noted for its immense outflow channels and chaotic terrain (McCauley and others, 1972; Sharp and Malin, 1975; Baker, 1982, chap. 3; Mars Channel Working Group, 1983). Various proposals for the origin of these features have been offered; most workers have favored a...