MORPHOLOGY AND LANDWARD SEDIMENT TRANSFER IN A TRANSGRESSIVE BARRIER ISLAND SYSTEM, SOUTHERN GULF OF ST-LAWRENCE, CANADA

The transgressive section of the Malpeque barrier system, Prince Edward Island, Canada, is a narrow, high dune shoreline retreating at an average rate of 0.26 m year-1. The barrier is maintaining its dimensions during retreat, largely by the landward transfer of sediment at the locations of present and former inlets. Calculations, based on the comparative analysis of vertical air photographs, indicate that over 90% of the landward sediment transfer during the period 1935-1968 was inlet-associated. Of this amount, 45% occurred as shoreline and dune recovery at the sites of five short-lived, temporary tidal inlets. The well-vegetated dune surface in other locations generally prevented landward sand movement from the foreshore by storm overwash and wind transport. The coastal environment of the Malpeque shoreline differs from that of many transgressive barriers further south, largely because of the restricted sea conditions present in the southern Gulf of St. Lawrence. Comparisons drawn between this barrier system and analogous Atlantic seaboard barriers suggest that contrasts in dynamics as well as morphology exist amongst barriers in different coastal environments. © 1979.