Level, bench-like platforms edged with scarps facing the interior of the Martian Gorgonum Chaos basin may have formed in conjunction with an ancient ice-covered lake. These benches, however, lack the typical features of shorelines associated with wave and current transport and erosion, such as crescentic embayments, spits, barrier islands, and wave-cut cliffs. Rather, the basin-facing platform edges are commonly rounded and cumulate in planform, often evenly encircling buttes protruding above the level of the benches. The benches are postulated to have been formed by outward growth in a quiescent environment, possibly by deformative lateral flow of sediment below the ice-water interface in a perennially frozen lake due to the weight of the ice overburden.