Purfleet interglacial channel-fill deposits of the Ockendon Loop of the Thames at junctions 29 to 30 of the M25 (EHER 82796)

A geoarchaeological investigation in 2011 revealed interglacial channel-fill sediments from 330,000 years ago. Interesting finds included contemporary lithic artefacts and a sabre-tooth cat tooth, one of very few fossils of this species found on the British mainland.

June to July 2011. Watching brief. Oxford Archaeology carried out a Pleistocene watching brief on land along the M25 carriageway between junctions 29 and 30 as part of the M25 widening Scheme, Essex. Deposits of Pleistocene and Palaeolithic interest were identified along the Belhus and Ockendon cuttings, where further more detailed investigations were undertaken. Interglacial channel-fill sediments were revealed at the Belhus cutting, rich in a wide range of palaeo-environmental indicators, together with scarce lithic artefacts indicating contemporary activity in the vicinity. The palaeo-environmental evidence indicating peak interglacial conditions probably a little warmer than the present day. The channel-fill sediments were laid down in a river channel, surrounded by a mosaic of reed beds and patches of damp meadow, open grassland and densely vegetated woodland. The channel-fill sequence was dated to the Purfleet interglacial episode associated with MIS 9e, dating to approximately 330,000 years ago. Notable finds included recovery of a sabre-tooth cat tooth, one of very few fossils of this species found on the British mainland. <1>