The Maputaland Corridor: A Coastal Geomorphological Treasure

Abstract

Maputaland represents the southern limit of the east African coastal plain , flanked by the volcanic Lebombo mountain cuesta and the high-energy Indian Ocean. The terrain morphology of the region bears testimony to deep erosional incision and dramatic sea-level fluctuations since the early Cretaceous . The topography of the coastal plain is closely linked to the sequence of aeolian sand deposits that have been differentially weathered and eroded. The late Neogene shoreline has been exploited by the Phongola River . Under the Tshongwe–Sihangwane sand megaridge and the wetland systems towards the east, the truncated dune landscape of the Kosi Bay Formation perches groundwater, providing groundwater seepage and seasonal run-off to the coastal lakes . The extended parabolic dune systems of the KwaMbonambi Formation define the surface relief and confine interdune wetlands . The coastal lakes have evolved in response to Pleistocene sea-level fluctuations that have inundated river valleys up to 25 km inland and caused foredunes to be submerged several kilometres offshore on the shelf. Accretion of the high coastal barrier dune cordon during the Holocene isolated some coastal lakes and forced morphological changes in others. Management of this area with international conservation status must draw from the dramatic influences that geomorphic processes have had on this region.