RAPID COASTAL CHANGE DURING THE MID-HOLOCENE TO LATE-HOLOCENE - THE RECORD OF BARRIER ESTUARY SEDIMENTATION IN THE ROMNEY MARSH REGION, SOUTHEAST ENGLAND

A common problem facing sea-level researchers lies in determining the cause of rapid changes observed in coastal stratigraphic sequences. Su ch changes are commonly ascribed to the interaction of processes that operate over differing temporal and spatial scales, i.e. rapid local a nd regional sea-level trends and storm magnitude/frequency. At least s ome of the difficulty in distinguishing between these processes lies i n the often limited stratigraphic database upon which palaeoenvironmen tal reconstruction is based. Here, we present the results of detailed morphostratigraphic and micropalaeontological investigations from a se ries of sites located at the interface between the protective gravel b arrier complex of Dungeness and the barrier estuary sediments of Romne y Marsh, England. A period of rapid coastal regression is identified b etween c. 4500 and 3000 cal, yrs BP, during which time the sea level c ontinued to rise but was outpaced by sediment accretion and pear accum ulation. A subsequent acceleration in the rate of rise led to a revers al of this excess of sediment supply over sea-level rise, and to rapid inundation of the entire barrier estuary between c. 2800 and 1900 cal . yrs BP. At the local level, coastal development reflects an interdep endence between storms and long-term relative sea-level (RSL) rise: pr ocesses which lie at opposite ends of the magnitude/frequency spectrum . However, when viewed from a holistic perspective encompassing the Ho locene development of Romney Marsh as a whole, storms are of secondary importance in controlling coastal evolution. Rather, our study sugges ts that at this macro-scale coastal evolution responds primarily to th e combined effects of RSL rise and sediment supply.