Holocene Evolution of the Sixteen Mile Beach Complex, Western Cape, South Africa

Abstract

Abstract The Sixteen Mile Beach Complex is one of numerous active dune accumulations along the West Coast of southern Africa. The beach complex is composed of a sandy beach, coast-parallel dunes, and a dune cordon. Grain size analyses, calcium carbonate content, sand texture and composition, and radiocarbon ages were determined to understand the Holocene evolution of the Sixteen Mile Beach Complex. Changes in sand grain size and dune morphology allow the complex to be divided into three parts. The beach and the dune cordon at the southern end are composed of fine sand. The central beach has a rapid decrease in the fine sand fraction that coincides with the transition from the dune cordon to a single large coast-parallel dune ridge. The northern beach is composed of medium sand and consists of a series of prograded, vegetated coast-parallel dune ridges. The formation of these distinct regimes is a reflection of the different amounts of wave energy received by the complex from the predominant southwest swel...