GEOLOGICAL AND PHYSICAL SETTING, SEDIMENTS AND ENVIRONMENTS, WESTERN-PORT, VICTORIA

This paper assesses the physical and geological features of Western Port, Australia including the geological evolution, Holocene morphology, sediment distribution, sedimentation patterns and depositional environments. Interpretations were based on data from field mapping, aerial photographs, sediment sampling, depth profiling at selected sites, and limited SCUBA inspection. The complex shape of the bay is determined by geological factors and only minor stream discharge and associated sediment input occurs. Tidal activity is dominant and estuarine circulation is not well developed. Eight intertidal and subtidal environments have been recognised. Net long-term paths of sand transport and deposition, and zones of ebb dominance and flood dominance were delineated within the bay and suggest a landward reworking by tidal processes. The extensive intertidal environments show variable sediment distribution patterns of sand and mud, controlled by salt marsh, mangroves, and dense intertidal and subtidal seagrass meadows. Sand is concentrated mainly in tidal channels and associated subtidal offshore banks. Mud is dominant in the Embayment Head and in isolated intertidal areas, except where autochthonous sand is abundant. Suspended sediment is active in the channels, particularly near mud-rich intertidal areas. © 1979.