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BGS Technical Report WA/97/03 15 December 1997
5.1 'Older Drift'
The region was not glaciated during the late Devensian (Oxygen isotope stage 2) when ice
sheets overran much of northern England. Instead, the glacigenic deposits which occur both
as dissected cappings on the higher ground and as an infill of a palaeochannel cut through
bedrock (see below) have been collectively referred to as 'Older Drift'. These deposits are
currently thought to be Anglian in age (Oxygen isotope stage 12), dating back some 500 000
years BP, and indicate a greater overall amplitude of relief at the end of that glaciation than
now. The ice sheets at glacial maximum overwhelmed the entire region (see below). During
glacial meltout, meltwater streams deposited glaciofluvial sand and gravel along their courses.
The main trunk routes developed into the rivers Trent and Dove, which have subsequently
eroded and deepened their valleys to leave the glacial deposits as high level erosional
remnants. The glacigenic deposits were subsequently so strongly affected by later periglacial
degradational processes (frost shattering and mass movement), particularly in the late
Devensian, that they now lack any constructional morphology of glacial origin.
5.1.1 Oadby Till
During the Anglian glaciation of Central England ice-flow was initially from the north-west
with Pennine Ice advancing from the north. This was succeeded by ice that moved across from
the snow fields of Scandinavia and eastern Scotland (e.g. Rose, 1994). These separate ice
advances result in two basic types of till in the Loughborough - Derby region, namely a till
of northern 'Pennine Drift' provenance, and one of eastern 'Chalky Boulder Clay' provenance,
equivalent to the Thrussington and Oadby tills respectively of Leicestershire (Rice, 1968).
These correspond respectively with the Early and Middle Pennine boulder clays and Great
Chalky Boulder Clay of Deeley (1886). There is no known Thrussington Till preserved in the
Etwall area. The stone clasts in the local Oadby Till include chalk, flint, oolitic limestone,
Liassic bioclastic and argillaceous limestones, Liassic fossils including pyritised ammonite
fragments and bivalves (particularly Gryphaea), black fissile shale and calcilutite limestones
from the Penarth Group, as well as abundant Triassic lithologies.
Inevitably, regardless of the ice flow direction and provenance of the farther travelled stones,
the basal 1 m or so typically incorporates local bedrock from the Mercia Mudstone and the
matrix may have a red coloration. In adjacent areas, where the tills of the two provenances are
found in association, the Oadby Till always overlies the Thrussington Till and is therefore
consistent with a later glacial advance from the east and north-east. In these areas tills of
mixed origin occur locally, and it may be inferred that such hybrid tills result from the
reworking of Thrussington Till during the later glacial advance.
During glacial advance, the local base level of area was probably considerably higher than at
present in the Trent valley and may have been as high as about 70 m above OD. Consequently
the Oadby Till, other than that deposited in tunnel valleys beneath the ice (see below), is
generally only found capping hills above this height where it is considerably dissected.
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Oadby Till also partially infills the Elvaston Palaeochannel, which enters the south-eastern
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