The Clacton-on-Sea (Essex, UK) GCR site and SSSI: New data and continuing importance

The complex Geological Conservation Review (GCR) site at Clacton-on-Sea, Essex, was notified in 1986 as a Site of Special Scientific Interest. It is an internationally important geosite and Britain's only Lower Palaeolithic type locality, giving its name to the Clactonian stone-tool industry. Fossil- and artefact-bearing channel-fill deposits laid down by the River Thames ~ 420,000 years ago, during the Hoxnian Interglacial (Marine Isotope Stage 11c), have been observed in foreshore and cliff exposures, and beneath developed and open ground in an inland arcuate footprint. These sediments provide a record of the lower reaches and estuary of the Thames during this lengthy and warm interglacial, an important partial analogue for the Holocene. Palaeoclimatic and palaeoecological evidence has been obtained from assemblages of fossil molluscs, ostracods and vertebrates, together with pollen and plant macrofossils; Clacton is also the type locality for several of the represented animal taxa, including the biostratigraphically significant ostracod Scottia browniana and a large subspecies of fallow deer, Dama dama clactoniana. This paper provides an overview of the continuing importance of the Clacton GCR site and Site of Special Scientific Interest (SSSI), summarizing recently acquired data that have enhanced understanding of the Hoxnian and the palaeoenvironments that prevailed at the time of deposition. The wider geosite has benefitted from sustained Palaeolithic archaeological interest, with the local planning authority mandating investigation of the sediments as a condition for development projects. SSSI status ensures that the significant collections of palaeontological and archaeological material amassed from the Clacton deposits over almost two centuries can be related to their context, and studies of both these archived collections and new material from the protected in situ sediments continue to provide new data and contribute to the development of cutting-edge techniques.