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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 mechanism in which ground water or water-rich debris was expelled from beneath a frozen crust, leading to catastrophic debris flows or floods that may have contained significant amounts of ice (Baker and Milton, 1974; Carr, 1979; Nummedal and Prior, 1981; Lucchitta, 1982; MacKinnon and Tanaka, 1989). The channels originated on or...
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The geology of the Thaumasia region (fig. 1, sheet 3) includes a wide array of rock materials, depositional and erosional landforms, and tectonic structures. The region is dominated by the Thaumasia plateau, which includes central high lava plains ringed by highly deformed highlands; the plateau may comprise the ancestral center of Tharsis tectonism (Frey, 1979; Plescia and Saunders, 1982). The extensive structural deformation of the map region, which is without parallel on Mars in both complexity and diversity, occurred largely throughout the Noachian and Hesperian periods (Tanaka and Davis, 1988; Scott and Dohm, 1990a). The deformation produced small and large extensional and contractional structures (fig. 2,...
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The Valles Marineris region lies east of Tharsis Montes (which extend from lat 12˚ to 16˚., long 101˚ to 125˚). Part of the region is in the midst of a vast plateau bounded on the west and east by Claritas and Nectaris Fossae, respectively; the remainder extends farther east into southern Xanthe Terr and western Margaritifer Terra. Channel trends, stereophotogrammetry, and radar altimetery indicate that the surface north and east of the canyons slopes toward Chryse Planitia (centered at about lat 25˚ N., long 45˚). Within the broad Valles Marineris region, three distinct physiographic provinces are recognized (fig. 1): (1) the Noctis Labyrithus province, consisting of a high plateau cut by a network of structurally...
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Mangala Valles are a system of outflow channels cut into Terra Sirenum that appear to originate from a fracture of Memnonia Fossae radial to the Tharsis volcanic center (about 1,800 km to the east).
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The region centered at Elysium Mons contains the second largest volcanic complex on Mars, surpassed in size by only the Tharsis complex. The Elysium region also has been a center of tectonic, fluvial, and mass-wasting activity. After degredation of ancient cratered terrain within the northern lowlands, volcanic rocks erupted from the Elysium Mons, Hecates Tholus, and Albor Tholus in Elysium Planitia. The volcanic activity was associated with episodes of channel formation, faulting, and apparent volcano/ground-ice modifications of some areas.
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