Major Flandrian transgressive cycles, sedimentation and palaeogeography in the coastal zone of Essex, England

Abstract

The 36 m thick succession rests discordantly on sub-aerially weathered Pleistocene and older strata arid comprises 3 major marine transgressive cycles. The lower 2 are confined to the vicinity of deep Pleistocene channels whereas the 3rd, possibly initiated c. 7500 B.P. extends across the whole coastal zone. Each cycle consists of a lower division of clays and silts with thin coarser deposits towards the base and an upper division of sands and sandy gravels. The contact between the two divisions is often erosional or sharp. Landward displacement of the plain lithofacies is most pronounced during episodes of relatively rapid rise in sea level, as in the U.S.A. and Holland. At certain levels reached by the rising sea extensive bodies of relict Pleistocene sediment becamte available for marine reworking. The persistence of lagoon, marsh, beach, chenier, barrier, tidal flat and channel lithotopes through the succession in conjunction with 12 radiocarbon dates allow general palaeogeographic deductions to be drawn, more especially for c. 7500, c.4000 and c. 1350 B.P.