Setup, Deposition, and Sedimentary Characteristics of Two Storm Overwash Deposits, Abrahams Bosom Beach, Southeastern Australia

Two storm events occurred in the southwest Pacific Ocean in March and July 2001 and generated large swell from the east–northeast that breached a small barrier complex at Abrahams Bosom Beach on the southeast coast of Australia. Both events breached the barrier and deposited sandy marine sediment more than 150 m into the back-barrier estuary. The sandsheets consist of graded beds that are generally less than 20 mm thick. The periodic storm-generated swells that strike the coast from the north to northeast are not in equilibrium with the ambient setting of north-facing embayments on this coast. Such north-facing embayments are likely to be breached during episodic high-energy events. This project provided an opportunity to determine the sedimentary characteristics of overwash sedimentation in an estuary from the southeast coast of Australia. The overwash deposits also provide a modern analog to assist in the characterisation of other Holocene overwash sandsheets identified from estuaries along the southeast Australian coast.