Texture, Composition and Provenance of Beach Sands, Victoria, Australia

Abstract

Analysis of foreshore beach samples from 26 locations along the Victorian coast between Lakes Entrance in Gippsland and near Port Fairy shows great local variability in both texture and composition. The entire coast is exposed to waves from the Southern Ocean and beach orientations range over a spectrum of 150 degrees. Numerous headlands locally restrict shore-parallel transport except in the Ninety-Mile Beach region of eastern Victoria. Mean grain size of foreshore beach sediments ranges from very coarse sand to fine sand. Sorting is typically very good. Both slightly positive and slightly negative skewed sediments occur. Few textural patterns are apparent however, coarsest samples are from Cape Otway and Cape Schank with a decrease in grain size away from the Cape Otway headland. The common general relationship between mean grain size and sorting is not displayed because the coarsest beaches are among the most well sorted. The composition of Victorian beach sediments ranges greatly with quartz and biogenic skeletal fragments being most common. Feldspar is locally abundant. Most beach sediment is derived from proximal sources but there is indication of transport along significant portions of each coastal section.