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Volcanoes are among the most imposing and geologically interesting features on Mars. Nearly 60 percent of the planet’s surface is covered by volcanic rocks dating from the Early Noachian to Late Amazonian Epochs (Tanaka and others, 1988). This map of the volcano Apollinaris Patera and surrounding area is one of a series of large-scale (1:500,000) geologic maps initiated by the National Aeronautics and Space Administration to investigate areas of particular scientific interest. The areas selected for mapping contain candidate landing sites for future sample-return missions to Mars (fig. 1).
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These geologic and topographic maps show a basin in the Elysium region of Mars that is thought to have been the site of a large paleolake during the most recent period (Amazonian) in Mars' history (Scott and Chapman, 1991b). The basin, referred to as the Elysium basin, extends for more than 2,000 km across the lowland plains. It is important, not only geologically, but because the amount, location, and duration of liquid water that it may have contained would have been critical factors governing the possible origin and survival of life on Mars.
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Although geologic mapping fo the Moon has its own techniques and problems, systematic observation and the application of established geological principles have allowed the materials and structures of its surface to be delineated and classified into units (Shoemaker and Hackman 1962; McCauley 1967; Wilhelms, 1970). Most of these units are material entities similar to terrestrial rock-stratigraphic units and have been arranged in chronological sequence to form a lunar stratigraphic column. Relative ages are determined by superposition, embayment and cross cutting relations, and by density of superposed craters and degree of topographic freshness (Wilhelms 1970). In addition, crater morphologies are believed to be...
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The Beethoven quadrangle is located in the equatorial region of Mercury, in the center of the imaged area. Most pictures of the quadrangle were obtained at high sun angles as the Mariner 10 spacecraft receded from the planet. Images in the northeastern part of the quadrangle are very poor to unusable. Another difficulty in mapping is the poor match in topographic bases between Beethoven and adjacent quadrangles. Mismatches are especially common along the borders with the Kuiper and Discovery quadrangles to the east and southeast.
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The Elysium quadrangle includes part of the vast, relatively low and featureless plains that encircle the subpolar region of Mars immediately north of the more elevated and cratered equatorial belt. The plains are interrupted in the northwest by two large volcanoes, second only in size and youthful appearance to some of the large constructs that form the planet’s most prominent volcanic center in the Tharsis region several thousand kilometres to the east (Carr, 1975). The large irregularity shaped crater Orcus Patera, at the east boundary of the map, closely resembles the lunar crater Schiller but is more than twice as long. A band of knobby, relatively old terrain extends in a broad arc northeastward through the...
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