options then
A substance behaving a bit like a liquid may have existed and flowed on Mars in sufficient volume to create the observed features.
The length of time since this may have happened allows any surface traces to be weathered away or buried in meters of sand/dust.
The atmosphere has also appeared to have eroded subjecting the surface to an increasingly low pressure and increasingly high level of radiation.
Any flows may have been long and slow (i.e. glacial) or sudden and fast (e.g. seasonal flooding)
The latter would not necessarily be around long enough to create deposits in significant quantity to remain in the timescale, regardless of their possible deposition.
The former, one may imagine, would leave a more obvious terminal moraine of stone/boulders carried with the flows.
The diagnostic features may now have drifted into space, been pulverised into dust and irradiated, or buried at a more significant depth.
Or there is a completely different process creating the features, although I remain with the plausible view that there was some kind of flow/erosion going on.
Biting the hand that feeds IT
