The relationship between sedimentary history and geotechnical behaviour of Quaternary sediments in Holderness
The stratigraphy-, sedimentology and geotechnical properties of the
Quaternary sequence in Holderness were examined in detail, with the aim
of relating depositional history to observed geotechnical behaviour.
Both the Withernsea and Skipsea Till units were found to possess the
sedimentary and geotechnical characteristics of a diamict deposited
beneath a wet based ice sheet. No evidence could be found for the
downwasting of a complex stratified ice sheet as previously proposed
for the sequence.
Critical state theory was found to accurately predict the reaction
of the diamict to shear and was used to predict the behaviour under
theoretical stress/environmental situations.
An alternative depositional model is proposed which explains the
Skipsea - Withernsea Till succession as the product of the slow
accretion of basal debris under an active ice stream. The multiple
stratigraphy is interpreted in terms of a shift in the east coast flow
units, carrying distinct mixes of lithologies"along individual flow
lines, within a single ice sheet.
The key sections through the Quaternary in Holderness are reexamined
in terms of deposition from an active ice sheet. It is
concluded that-the Basement Till represents the initial advance of the
cold-ice margin and is Devensian in age rather than pre-Devensian as