COASTAL FORMS AND QUATERNARY PROCESSES ALONG THE ARID PILBARA COAST OF NORTHWESTERN AUSTRALIA

The Pilbara coast is set in the most arid part of coastal Australia. T his coast and coastal plain, composed of riverine plains, deltas, tida l flats, coastal dunes and limestone barriers, relic deltas and archip elago/ria shores, is predominantly a terrigenous and carbonate sedimen t complex. The coastal landforms therein formed during the Quaternary through influence of ancestral landforms and fluvial and shoreline acc retion, coastal erosion, and cementation. The pre-Holocene features co ntrolled development of Holocene coastal forms and a variety of Holoce ne depositional styles. Climate also plays a significant part in the c oastal processes and in the generation of sedimentary products through high evaporation rates coupled with the limited rainfall, cyclonic st orms, wind, wind waves, and the limited sediment delivery to the coast al zone. This results in a distinctive range of stratigraphic sequence s and chemical products. As a result, this arid coast is characterised by a range of features such as construction of arid-zone deltas, delt a destruction and sediment redistribution during times of sediment dep letion, cyclone-induced erosion and sedimentation, mangroves and their associated sedimentary deposits, evolution of coastal groundwater hyp ersalinity, formation of salt flats, and precipitation and cementation to form beachrocks, high-tidal crusts and gypsum precipitates. The Pi lbara coastal stratigraphy and geomorphology suggests aridity was intr icately involved in the sedimentation, geomorphic evolution, and pedog enic and diagenetic alteration of this coastal zone throughout the who le of the Holocene and Pleistocene.