Areas around western Vestfold Hills, East Antarctica, feature two sedimentary units in outcrops and excavations. Uppermost Dingle Sand is a gravelly, silty sand with boulders, which drapes bedrock ridges and more thickly covers valley floors and continues below modern sea level. Underlying Vestfold Beds are gravelly, muddy sands that are found in deeper valley fills. High-resolution aerial photography, topographic and bathymetric surveys, sediment grain size and field observations indicate that Dingle Sand formed as ablation till during the last deglaciation. Post-depositional modifications of Dingle Sand by decay of ground ice, mass movement, water, wind and marine transgression and regression have altered the texture, structure and fossil content in this region. Vestfold Beds are older, finer-grained tills. Indirect age estimation of Dingle Sand suggests deglaciation-age deposition with younger (Holocene) reworking in places, whereas Vestfold Beds may be as old as the Pliocene. These sediments post-date the early Pliocene Sørsdal Formation found on Marine Plain in southern Vestfold Hills. Identification of Dingle Sand as a separate, primarily glacial deposit helps clarify the glacial history of the Vestfold Hills. Evidence for marine modification of the deposits after deglaciation suggests that other regions might also have glacial deposits interpreted as marine because of post-depositional processes.

Topographic models of the late Quaternary landscape prior to isostatic rebound aid interpretation of glacial lake-water levels and geomorphic features as well as ice thickness, mantle viscosity and lithospheric strength. The well-established limit of glacial marine inundation in central and northern New England provides a test of total isostatic depression. Relative sea levels reflecting differing magnitudes of isostatic rebound show that published values of isostatic depression in southern New England would inundate the landscape in southern New England with marine water south of the limit of late Pleistocene marine inundation. This suggests that isostatic depression at the terminal margin of the Laurentide Ice Sheet (LIS) was < 35 m, and that previous workers overestimate isostatic depression in southern New England by > 50 m. A first-order estimate of ice thickness based on total isostatic depression and the observed uplift profile in southern New England supports the ‘thin ice’ models in New England. Ice thickness ranged from 100 m at the southeastern margin of the LIS, to > 1000 m at a point 300 km north of the terminal margin. This regional model places constraints on continental ice-sheet and geophysical models that should be considered in the future.