Basic Types of Dunes - Dune Worlds: How Windblown Sand Shapes Planetary Landscapes - page 79

Fig. 6.15 Part of the Belet sand sea on Titan. At the right, dark dunes
interpreted to be linears are seen against the bright background of a
highland terrain extending to the top. In the middle of the image, a set

of near-vertical features can be seen, interpreted to be transverse
dunes. Image R. Lorenz/Cassini Radar Team/NASA/JPL

Fig. 6.16 Transverse ridges on Mars. HiRISE image ESP_016036
_1370. In the present epoch, it seems appropriate to call these transverse
ridges, in that they have a uniform slip face orientation which is
consistent with that shown by the wide 'wing' barchans at the bottom
(which are departing from the main dunefield). It is a separate question

whether the sand accumulated into these very parallel and regular forms
is in the same wind regime as at present—one possibility is that these
were linear dunes and subsequently had a unimodal wind regime
imposed on them. Image NASA/JPL/U, Arizona