Published:January 01, 1999
The sequence and nature of Quaternary events have been determined principally from evidence in coastal sections, cave sequences and extensive spreads of unconsolidated sediments in the Somerset and Avon lowlands. Correlation is hampered by their isolated nature and scarcity of samples for dating. It is generally agreed that Southwest England was not overrun by Pleistocene ice sheets. Fragmentary evidence for the encroachment of an ice sheet along the present north coast, from the Isles of Scilly to north Devon, is, however, widely recorded. It takes the form of giant erratics on shore platforms (e.g. Saunton), possible glacigenic gravels (Isles of Scilly, Trebetherick and Lundy Island) and glacial deposits (Fremington) (Stephens 1973). This has led to the notion that the most extensive of the Pleistocene ice sheets reached its southernmost limit at or near the north Devon and Cornish coasts.
Figures & Tables
A revised correlation of Quaternary deposits in the British Isles
Realization that continental records of Quaternary rocks were more complex that hitherto believed came with the re-interpretation of oxygen isotope stratigraphy in the late 1960s and early 1970s. This necessitated a comprehensive re-evaluation that has been assisted by the emergence of new geochronological methods for terrestrial as well as land-sea correlations. The current state of such correlations is presented in this revised set of proposals for correlations in England, Ireland, Scotland and Wales, which also includes the Quaternary geology of the continental shelf. Correlation with the global standard of oxygen isotope stratigraphy enables the significance of British lithostratigraphical units to be appreciated in a wider context that includes the evolution of the climate system on the margin of the northeast Atlantic Ocean. It thus provides timely British data for the international palaeoceanographical and palaeoclimatological community and the correlations proposed are primarily on Milankovitch timescales. But their appearance coincides with the early stages of a paradigm shift to the search for both terrestrial and land-sea correlation on millennial timescales and then on centennial and decadal ones. This is the first of many similar terrestrial and land-sea correlations.