The Pleistocene sequence of the Telford district

Abstract

The Pleistocene (Late Devensian) sequence of the Telford district is more complex than previously thought. Several sub-glacial drift-filled channels cut the Wenlock Edge—Lilleshall watershed. One of these, the Lightmoor channel, has been traced for 20 km, leading from the Buildwas Sands, which are interpreted as sub-glacial. The Oakengates and Mad Brook channels contain both sub-glacial and later fluvio-glacial sediments, and the deposits of two further sub-glacial channels occur at Ketley. All the deposits south of the main watershed are assigned to a single ice advance and retreat, but north of the watershed lacustrine deposits include two tills, possibly indicating an earlier advance as far as Ketley. Late-glacial lacustrine deposits at Lilleshall are referred to Glacial Lake Newport, and a Glacial Lake Buildwas may also have existed, overflowing through the Ironbridge Gorge, but it is not considered that they ever coalesced to form a grand Lake Lapworth. The Ironbridge Gorge was initiated primarily as a channel marginal to the ice-sheet when the latter stood immediately north of the present course of the Severn.