A reconsideration of the origin of the early Pleistocene ‘Pebble Gravel Formation’ at Nettlebed, Oxfordshire, south central England

It is proposed that the meagre ‘Nettlebed Gravel’ does not merit its designation as the earliest sedimentary archive of the River Thames, nor is it a degraded river terrace. Rather the character of the gravel supports a derivation by slope processes with a quartz/quartzite component primarily sourced by the underlying Palaeogene Reading Formation. The associated Priest's Hill pollen bearing sediments are probably the infill of either a local palaeochannel or a doline. Although the ‘Nettlebedian Interglacial’ is likely to be early-middle Pleistocene in age, it bears no direct relationship to the Thames fluvial chronology. As a consequence any marine oxygen isotope stage assignment is unrealistic.