Competing mechanisms for boulder deposition on the southeast Australian coast

Abstract

This study investigates the role of late Holocene sea-level change, large storms and possible pre-historic tsunami in the deposition of boulder features on an exposed headland and sheltered rock ramp. Large accumulations of boulders are found on coastal rock platforms, cliff tops and ramps in the Jervis Bay region of southeastern Australia. These deposits are elevated above sea-level and in places exhibit obvious signs of imbrication as a response to flow in a landward direction. The event history of these features is controversial and Holocene sea-level change, storms and tsunami can be considered as possible, non-mutually exclusive mechanisms of deposition. It is apparent that even if the detachment site, transport distance, elevation and final orientation of a boulder can be identified, deciphering the event history remains a difficult task.