Channels and valleys on Venus: preliminary analysis of Magellan data

A preliminary survey of Magellan imagery reveals more than 200 newly discovered relict channel and valley landform complexes. Simple channels include 1) sinuous rilles that closely resemble their lunar counterparts and 2) a newly recognized long sinuous form of high width-to-depth ratio and remarkably constant width. Herein designated canali, the most spectacular of these channels is 6800 km long. Streamlined hills and spill relationships at a cross-axial ridge are similar to features in flood channels. Venusian channels have a global distribution with most of the large canali-type channels developed on volcanic plains. Alternative hypotheses for the channel-forming processes include genesis by the following erosive fluids: ultramafic silicate melts, sulfur, and carbonate lavas. -from Authors