The pleistocene geology and geomorphology of western Leicestershire
thesisposted on 08.02.2010, 11:14 by Terry David Douglas
The Pleistocene stratigraphy of an area of 116 km2 in western Leicestershire was mapped largely by means of a hand-auger. The investigations revealed the following sequence: Flinty Gravel, Chalky Till, Pennine Till, Cadeby Sand and Gravel Bosworth Clay, Basal Till. The vicinity of the sand and gravel workings at Cadeby was selected as the type site. The sub-drift surface of the area is dominated by the Hinckley valley, a major left bank tributary of the proto Soar. The Basal Till contains erratics of a predominantly, but not exclusively, northern provenance and betokens an ice advance prior to the accumulation of the Bosworth Clay, an extensive glacio-lacustrine formation. This proglacial lake is regarded as part of Lake Harrison which was initiated on the retreat and stagnation of ice following the deposition of the Basal Till. A subsequent readvance of the ice led to the deposition of a large sandur over the lake deposits and subsequently a till sequence comprising both Pennine and Chalky Till varieties. Till macrofabric analysis supports an interpretation of much of the Pennine Till as a lodgement till but overlying 'banded tills' indicate the contemporaneous deposition of chalky material, possibly through melt-out from a compound ice sheet. This sequence of deposits is readily correlated with that described by Shotton in the Avon valley and has been matched with Rice's succession in the Leicester area. The entire sequence is regarded as the product of one Wolstonian stadial. Sands in the cores of Devensian involutions are probably the remnants of a once extensive sheet of aeolian material.