Dja. Evans et al., STRATIGRAPHY AND SEDIMENTOLOGY OF DEVENSIAN (DIMLINGTON-STADIAL) GLACIAL DEPOSITS, EAST YORKSHIRE, ENGLAND, JQS. Journal of quaternary science, 10(3), 1995, pp. 241-265
The stratigraphy and sedimentology of the glacial deposits exposed alo
ng the coast of east Yorkshire are reviewed. Critical sections at File
y Brigg, Barmston and Skipsea are examined to reassess the stratigraph
y of Devensian Dimlington Stadial glacial deposits in the light of rec
ent developments in glacial sedimentology. Sedimentary and glaciotecto
nic structures studied in the field and by using scanning electron mic
roscopy are emphasised. Two hypotheses are considered for the genesis
of the interbedded diamictons and stratified sediments. The first invo
lves the deposition of lodgement till and/or deformation till followed
by meltout till, which was overridden to produce more deformation til
l, reflecting periods of ice stagnation punctuated by glacier thickeni
ng. The second hypothesis, which is favoured on the basis of field evi
dence and micromorphology, involves the vertical accretion of a deform
ing till layer associated with cavity/channel or tunnel valley fills,
beneath active ice. At Barmston the upper part of the diamicton contai
ns elongate pendant structures containing gravels, indicating that the
diamicton was saturated and able to flow. The diamictons, therefore,
represent a complex sequence of tills deposited and deformed by active
ice during the Dimlington Stadial. Previously published stratigraphic
al schemes involving classifications of multiple tills in east simplif
ied and it is more appropriate to assign these to a single formation,
the Skipsea Till Formation. Rhythmic glaciolacustrine and proglacial g
laciofluvial sediments overlie the tills at Barmston and Skipsea. Thes
e were deposited in sag basins during deglaciation as the tills settle
d and deformed under thickening sediment and as buried ice melted out.
Extensive sands and gravels cap the succession and were deposited on
a sandur during the later stages of deglaciation.