The back‐barrier and barrier depositional history of Romney Marsh, Walland Marsh and Dungeness, Kent, England

Abstract

Previous stratigraphical investigations of Romney Marsh have tended to be local in scale, and this has hindered efforts to establish a unifying stratigraphical framework for this area. This paper addresses this problem, by describing the results of a 12-km transect across Romney Marsh, linking previously studied back-and fore-marsh sites (Horsemarsh Sewer and Broomhill respectively), and presenting additional pollen, diatom and radiocarbon data from an intermediate, mid-marsh site (Brookland). One main organic unit is recorded across much of Romney Marsh, although its age, altitude and composition varies. Microfossil and radiocarbon data from Brookland and elsewhere on Romney Marsh show that this organic unit accumulated under a general removal and return of marine conditions that took place between ca. 5100 and 2000 yr BP.A recently proposed model of barrier development is used to investigate the history of backbarrier sedimentation in Romney and Walland Marshes. This model suggests a three-phase lifehistory for gravel barriers, which consists of initiation, stability and breakdown. Although there are problems in relating back-barrier deposits directly to barrier dynamics, nevertheless the Romney Marsh data do, for the most part, agree with the expected number and sequence of sealevel tendencies predicted by this model. The back-barrier stratigraphical data suggest that initiation, stability and breakdown of the Dungeness foreland occurred between ca. 6000 and 5000 yr BP, 5000 and 2000 yr BP and 2000 yr BP and present, respectively. Journal of Quaternary Science

The Holocene coastal deposits of Sussex: a re-evaluation

“…A broadly similar three-phase model of barrier development was applied by Long and Innes (1995) to Romney Marsh/Dungeness, although the chronology differs significantly to that of Jennings and Smyth (1990). Based on an interpretation of barrier and backbarrier records, they proposed that barrier initiation occurred c. 6500-5000 cal.…”

“…Barrier breakdown, the segmentation and reorientation of the barrier, in the last 2000 cal. yr BP resulted from a decline in the supply of sediment, an increase in storm magnitude/frequency or accelerated RSL rise (Long and Innes 1995).…”

“…In most of the boreholes sunk across Walland Marsh and Romney Marsh proper (e.g. Long and Innes 1995;Long et al 1998) sand (impenetrable by hand-coring) is recorded at a depth of c. -3 m OD. Termed the 'Midley Sand' by Green (1968), these deposits are now known to be stratigraphically distinct from the surface sand deposits regarded by Green as part of the same unit (Long and Innes 1993).…”

“…Across the western side of Walland Marsh (from Horsemarsh Sewer to Pett Level) a thin (c. 10 cm) layer of peat occurs, intercalated between clay layers, prior to the formation of the main Marsh peat (Tooley and Switsur 1988;Waller et al 1988;Long and Innes 1995). The latter is a laterally persistent peat bed which varies in thickness from c. 6 m in the valleys to <1 m on Romney Marsh proper, though locally in one of the small tributary valleys (the Pannel), it is thicker and extends to the surface (Waller 1993).…”

“…Jennings and Smyth 1987;Smyth and Jennings 1988;Burrin and Jones 1991) and new work has been undertaken, not only from the Romney Marsh area (e.g. Waller et al 1988;Long and Innes 1995;Plater et al 1999;Long et al 2007), but also from Pevensey Levels (Lake et al 1987;Jones 2002), Willingdon Levels (Jennings et al 2003) and the Ouse valley (Waller and Hamilton 2000). In addition, knowledge of a number of key processes, in particular sea-level change (Long and Shennan 1993;Waller and Long 2003), the development of the gravel beaches Nicholls 1991) and sediment input from terrestrial sources (e.g.…”