Holocene transgressions and regressions on the Essex coast outer Thames estuary

Abstract

Faunal and lithological changes within the 34 m of Holocene sediments of the chenier plain suggest six episodes (l-VI) of marine transgression interspersed with five episodes of regression. Evidence presented for recognising transgressions includes chenier formation, marsh retreat and vertical changes in fauna, involving brackish water and intertidal molluscs. Regressions are interpreted chiefly from geosols and peat seams. Radiocarbon dates indicate that the transgressive episodes lI, lll and V first affected the region at about 7500, 4000 and 1400 B.P. respectively. The most recent one (VI) probably commenced about 300 B.P. The dates of episodes I and IV can only be conjectured. Comparison with similar events globally as well as in the Low Countries suggests that eustatic changes in sea level have played a significant ¡ole in the Holocene history of the Outer Thames estuary.