Structures in deposits from beach recovery, after erosion by swell waves around the southwestern coast of Aruba (Netherlands Antilles)

Abstract

Hurricane- or storm-generated swell waves may cause erosion and deposition along coasts which are situated thousands of kilometers outside the generating wind field. Marked beach erosion, caused by such swell waves, was observed along the micro-tidal west coast of Aruba. During the process of erosion a swash bar was formed, which moved up-beach during the waxing part of the swell event. The swash bar welded to the beach during the waning part of the event. Rapid sedimentation occurred on the upper beach. Finally, recovery of the beach was observed. The formation of a swash bar was attributed to an erosive, dissipative interval of a normally accretionary reflective beach. The sedimentary structures, although generally in line with observations on other beaches, show several peculiar characteristics: (1) the great thickness of the laminae in these calcareous sands; (2) the succession of low-angle sigmoidal and tangential sets in the swash bar; (3) the relatively steep erosional lower set boundaries and the wedge-shaped lamination in the successive stages of beach recovery; and (4) the several types of deformation structures.