In the following image, typical for the surface of Mars, note the long straight channels formed when CO2/H2O clathrates are released by heat generated during the entry of an impactor meeting the planet at an angle low to the planet's surface, that is to say "obliquely":

http://themis.la.asu.edu/mars-bin/mars_cgi_map.pl?CENT_LAT=-37.37097176&CENT_LON=170.1670353&RESCALE=64&TNAIL_LINK=20020611a

The assumptions of this articles' authors are that marseological processes for "lake formation" and "channel carving" are identical to the geological processes which occur on the planet Earth, which is hardly likely to be the case, as the lithospheres of each planet are very different.

Most likely, what occured was a rather fast release of clathrate, with the accompanying observed flows, but one could not tell without a detailed examination of the cratering found in the features. Even given this, dating any process on Mars will require far better crater counts than those currently available.

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