Central West Western Australia Region

Abstract

The central west region of Western Australia is a generally arid section of coast extending from the Murchison River mouth north to Exmouth Gulf and including Shark Bay, with a total shoreline of 1660 km. While two larger rivers, the Murchison and Gascoyne, reach the coast building extensive deltas, this is predominately a carbonate-rich coast, with sediments derived from the inner shelf limestone platform and in Shark Bay the extensive carbonate banks and their seagrass meadows. The open coast is exposed to persistent moderate to high southerly swell which in the north is attenuated and refracted across the Ningaloo fringing reefs, while Shark Bay and Exmouth Gulf have sheltered shorelines. Tides are micro the length of the open coast and in Shark Bay, increasing to meso into Exmouth Gulf. The coast is a mix of calcarenite and bedrock bluffs and cliffs and beach systems which range from exposed wave-dominated to very shelter tide-dominated in the bays. Likewise, barrier systems range from extensive regressive systems associated with the deltas to massive Holocene dune transgression, much overlapping Pleistocene dune calcarenite, which rises to 250 m along the Zuytdorp Cliffs, with most capped by extensive Holocene clifftop dunes. This chapter examines the region’s coastal processes, beaches, barriers, sediment transport and sediment compartments.