Hydrodynamic Process Controls on Coral Reef Platform Sedimentation and Island Formation

Abstract

Coral reef islands are accumulations of unconsolidated carbonate sand and gravel deposited on reef platform surfaces by ocean waves and currents. Wave action is the primary control on sediment transportation processes which define the morphological construction of reef top islands. On platforms which exhibit a curved periphery wave refraction and convergence patterns control the transportation and deposition of sediment across reef flat surfaces. Reef configurations which promote centripetal wave motion demonstrate transfer of sediment towards central reef regions and may accumulate reef top islands. In contrast, platforms which feature an off reef wave focus exhibit a high potential for evacuation of sediment over leeward reef margins and the formation of subtidal sand aprons behind the platform structure.