Venus: Preliminary Topographic and Surface Imaging Results from the Pioneer Orbiter

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Science  06 Jul 1979:
Vol. 205, Issue 4401, pp. 90-93
DOI: 10.1126/science.205.4401.90


Three large Venus surface features, identified previously in images obtained from Earth-based radar observations, are shown by the Pioneer Venus radar mapper to be elevated 5 to 10 kilometers above the surrounding terrain. Two of these features, one bright and the other dark, lie adjacent to each other astride the 65°N parallel between longitudes 310°E and 10°E. The combined region forms a huge tectonically uplifted plateau, surmounted by radar-bright ridges that may have either a volcanic or tectonic origin. The third feature, located at 30°N, 283°E, is radar-bright and may consist of volcanic material extruded along a fault zone. A first radar-scattering image, compiled from data obtained by the mapper in its imaging mode, shows a region north of the equator; several circular depressions seen in this area may result from meteoritic impact.