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.
The style of Quaternary deposits in Wales is influenced by its Palaeozoic rocks and surrounding offshore, partly onshore, basins of Mesozoic and Cenozoic ones. Its dissected plateaux and mountains were the source areas for ice that spread on to the lowlands that were also, in part, glaciated by contemporaneous ice from the Irish Sea Basin.
The stratigraphical record in Wales consists mainly of glacial deposits with the source areas of the ice indicated by erratics in the Meirion, Elenid, Eryri (Snowdonia), Brecknockshire (of Breconshire), Rhondda and St Asaph Formations. Within the Late Devensian glaciated areas any record of earlier...