Humberside Geologist no 10
published 1992
In the last 2 million years there have been several advances and retreats of ice in the Northern Hemisphere. The record of these movements is incomplete in most places on land, due to glacial erosion. In general ice sheets tend to be erosional in their central parts and depositional towards their edges.
Hoxnian Stage. This stage ended some 250,000 to 300,000 years so. Deposits exist in the buried channel at Kirmington, Lincolnshire, the Speeton Shell Bed and perhaps the Bridlington Crag deposits.
This was followed by a long period of glaciation which covered most of Britain. Yorkshire was probably covered with various deposits but they have been removed by a later glaciation. This is named the Wolstonian Stage. This deposited the Basement Till of Holderness and Filey Bay. Most of this occurs below the sea but the last glaciation pushed some of it onto the land at Bridlington and Dimlington. Perhaps some of this overlies the Speeton Shell Bed. The ice moved from the NNE to SSW. It deposited a dark grey-brown boulder clay which has a wide variety of distinct Scandinavian rocks in it.
The Ipswichian Interglacial followed the Wolstonian some 120,000 years ago. Temperatures were at least as warm as at present and the coastline ran from Sewerby through Driffield and Cottingham to Hessle. The buried cliff at Sewerby was formed. Many large mammals lived in the area including elephant, hippopotamus, bison and rhinoceros. Kirkdale Cave was a hyena den.
About 60 to 70,000 years ago the last glaciation commenced - the Devensian Stage. This was not a period of unrelieved Arctic conditions; there were several short warm periods (Interstadials), where temperatures were as warm as present. The maximum extent of the ice occurred around 13,000 years ago. These short periods of intense and rapid climatic change in the relatively recent past and the absence of subsequent glacial erosion means evidence is well preserved and accessible.
Ice moved from the Pennines and from the Durham and Northumberland coasts. The ice carried much moraine and this now covers much of Holderness. Actual glaciation in Holderness was late in the period. The ice was here for only about 4,000 years and had gone about 12,500 years ago. When it retreated two distinct Tills were deposited. The Skipsea Till is up to 8 metres thick and is overlain by the Withernsea Till. Along the margin of the Withernsea Till, extensive areas of sand and gravel were deposited.
The Tills are now subject to rapid erosion. The beaches along the Yorkshire coast are covered with a wide range of rocks and fossils carried here from other areas by the ice and now are being washed out of the Tills.
Knowledge of the recent past is increasing. So far most studies have been on the land - it has been described as 'trying to count the number of times a blackboard has been cleaned', as one glaciation tends to destroy the evidence of earlier ones. Research is now taking place on the sea floor deposits. Sedimentation is a more complete record of events and sea bed research has been described as 'like counting the number of times a wall has been painted'.
copyright Hull Geological Society 2021