MORPHOMETRY OF WRINKLE RIDGES ON VENUS - COMPARISON WITH OTHER PLANETS

The widths of wrinkle ridges on Venus and the spacing of their network were measured at 30 randomly selected sites on the Venusian plains. A t one of the sites, heights of ridges were also estimated. Results of our measurements indicate that (1) wrinkle ridges on Venus form a quas i-periodic rather than chaotic network; (2) there are regional variati ons of the typical spacing within the network, with the mean for all 3 0 sites being 12.9 km, and the standard deviation of the means of all sites being 5.8 km; (3) there are regional variations of typical ridge width with the mean width being 1.25 km, and the standard deviation o f the means of all sites being 0.66 km; (4) there is no site-to-site c orrelation between the mean ridge widths and spacings. Comparison with other terrestrial planets shows that wrinkle ridges on Venus are gene rally narrower than on the other planets, and the spacing of the ridge network on Venus is smaller than on Tharsis Plateau, Mars. Global sur face shortening due to formation of the wrinkle ridge network is estim ated to he of order of 0.1%.