Giant “combs” on Mars
Old ripples
April 25, 2016Craters and wind
May 9, 2016
A Piece of Mars: This 480×270 m (0.3×0.17 mi) scene shows a herd of 100-300 m fine-toothed combs grazing on the surface of Mars. Wait, what? No, it’s not really combs. This is actually a landscape covered by two sets of windblown bedforms. The larger ones (the “comb” shafts) are very old, now inactive windblown features. The smaller ones (the “comb” teeth) are ~2 m apart, and they extend downwind (eastward) from the older bedforms, which effectively serve as filters that block winds from the west (left to right), allowing only the northerly or southerly components of most winds to shape the ripples on their lee sides. Beyond the influence of the larger bedforms, the small ripples merge with those on the surrounding sand sheet, which show the influence of several different winds (HiRISE ESP_045166_1690, NASA/JPL/Univ. of Arizona)
1 Comment
Beautiful! Mars has such a diversity of aeolian patterns showing on it’s surface. I think it must surpass Earth in it’s variety. Maybe this happens because Mars’ wind processes are so much less forceful that the canvas never gets wiped clean.
There’s one big inter-ripple just left of centre where the small background ripples appear to be arranged in lines that correspond to (extend from) the “teeth” of the “comb”. Just another fascinating detail.