The Moreton Drift: a further clue to glacial chronology in central England

A detailed survey of the area around Moreton-in-Marsh has clarified the nature of the glacial 'Moreton Drift' and its relationships to the river terrace deposits in the area. The 'Moreton Drift' is divided into several members based on lithology and genesis; the stratigraphy is strikingly similar to that of the correlative Wolston Formation of the central Midlands of England, which has been assigned to the Anglian Stage. The Moreton Drift includes two separate phases of glacial outwash gravels, an older phase, characterized by Trias-derived erratic material, and a younger flint-dominant phase. These two phases appear to equate with fluvial terrace deposits assigned, respectively, to the Freeland and Wolvercote members of the Upper Thames Valley Formation. The chronological significance of this correlation is discussed and it is concluded that the Moreton Drift and Wolston Formation must embrace two separate glacial events which, on the basis of currently accepted chronology, must be assigned to Stages 12 and 10 of the deep-sea oxygen isotope record. In addition, relationships between units of the Baginton and Northern Drift formations constrains the chronology of pre-Anglian drainage development.