@DrEvanGowan well I think it's interesting because of something I once saw about #Patagonia #icesheet the idea being that early #Quaternary glaciations had larger extent because of topography but these carved the landscape into a more efficient shapes (efficient for ice flow I mean), so later in the Quay thr #PatagonianIceSheet could not reach a similar extent.
I guess this is like the regolith hypothesis which (I presume, I haven't read it yet!) you were sort of testing here?