P.G. Ford W.E. Brown W.M. Kaula H. Masursky E. Eliason G.E. McGill G.H. Pettengill 1979 <p><span id="_mce_caret" data-mce-bogus="1" data-mce-type="format-caret"><span>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.</span></span></p> application/pdf 10.1126/science.205.4401.90 en American Association for the Advancement of Science Venus: Preliminary topographic and surface imaging results from the Pioneer Orbiter article