Geology and geomorphology of the Palaeolithic site at High Lodge, Mildenhall, Suffolk, England

The geology of the High Lodge site at Mildenhall is described and re-interpreted as a sequence of deposits related to a doline formed in the underlying Chalk. Doline development in the area is considered in detail. Lacustrine sediments filling the depression contain a Palaeolithic industry and pollen assemblages that indicate contemporaneous coniferous woodland. The High Lodge sequence, at the northern end of the Warren Hill ridge, is related to the Three Hills site at the southern end of the ridge and to recent exposures near the Beech Clump, midway on the ridge. The geology of the three sites combines to demonstrate a series of ice-marginal proglacial successions along the west and south side of the Warren Hill ridge, marking a glacial limit. This Skertchly Line limit, on the eastern flank of the Fenland, resulted from the Tottenhill ice advance into Fenland late in the Wolstonian Stage (c.160 ka; during Marine Isotope Stage [MIS] 6). Structural evidence indicates that the doline filling was initially thrust glaciotectonically by the glacial ice. These sediments were subsequently disturbed by diapirism arising from loading by meltwater deposits and possibly by periglacial processes. The doline strata predate the ice advance and represent a period of cool temperate vegetation, probably of interstadial character, earlier in the Wolstonian, during MIS 7. The High Lodge Palaeolithic industry is associated with this cool temperate period, not with pre-Anglian times as formerly proposed. At Three Hills, artefacts occur within the proglacial deposits and are reworked from an earlier period. The geomorphology of the Warren Hill ridge is described and an interpretation of the ice front presented. The relation of the area to the wider Fenland landscape development is discussed.