Sedimentology and Geomorphology of the East Marine Region: A Spatial Analysis

This report presents the geomorphology and sedimentology of the East Marine Region. Thethree main outputs of the report include: 1) a review of previous geological research undertaken inthe East Marine Region (EMR); 2) the results of a quantitative study of seabed sediment texture andcomposition for these regions; and 3) a synthesis of this information characterizing regional trends insedimentology, geomorphology and bathymetry. The study is a collaboration between GeoscienceAustralia and the Department of the Environment, Water, Heritage and the Arts (DEWHA) and is acontinuation of similar work conducted for the North West Marine Region (Potter et al., in press;Baker et al., 2008) and the South West Marine Region (Richardson et al., 2005). By combining resultsof previous qualitative work and quantitative information generated from existing and new data, thisreport provides an improved understanding of sedimentology for the EMR. Information containedwithin this report will contribute to the Department of the Environment, Water, Heritage and the Artsnational work program and will also assist in the marine bioregional planning for the East MarineRegion.Previous sediment studies in the EMR have predominantly produced qualitative results at local scales.Geomorphic, sedimentary and biological information has previously been utilised to develop aNational Bioregionalisation of Australia's Exclusive Economic Zone (EEZ) (Department of theEnvironment and Heritage (National Oceans Office), 2005; now the Department of the Environment,Water, Heritage and the Arts) and substantive geomorphic features of the eastern continental marginshave already been identified and mapped (Heap and Harris, in press). This report addssignificantly to these previous studies by incorporating the information in a sedimentologicalsynthesis that includes a discussion of the implications for marine conservation in the EMR.The physical characteristics of the seabed in the EMR, as described by the sediment texture andcomposition data, can assist in determining the diversity of benthic marine habitats in the EMR. Thesedata represent enduring features which are elements of the physical environment that do not changeconsiderably and they are known to influence the diversity of biological systems. This is importantfor marine conservation by contributing to the better definition and characterisation of benthichabitats. Seabed texture and composition are easily measurable parameters that when combined withother physical features can be used to create "seascapes" that serve as broad surrogates for benthichabitats and biota (Whiteway et al., 2007). Seascapes have the potential to be used in informing themarine bioregional planning process.