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

This report presents the geomorphology and sedimentology of the East Marine Region. The three main outputs of the report include: 1) a review of previous geological research undertaken in the East Marine Region (EMR); 2) the results of a quantitative study of seabed sediment texture and composition for these regions; and 3) a synthesis of this information characterizing regional trends in sedimentology, geomorphology and bathymetry. The study is a collaboration between Geoscience Australia and the Department of the Environment, Water, Heritage and the Arts (DEWHA) and is a continuation 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 results of previous qualitative work and quantitative information generated from existing and new data, this report provides an improved understanding of sedimentology for the EMR. Information contained within this report will contribute to the Department of the Environment, Water, Heritage and the Arts national work program and will also assist in the marine bioregional planning for the East Marine Region. 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 a National Bioregionalisation of Australia's Exclusive Economic Zone (EEZ) (Department of the Environment 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 margins have already been identified and mapped (Heap and Harris, in press). This report adds significantly to these previous studies by incorporating the information in a sedimentological synthesis 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 and composition data, can assist in determining the diversity of benthic marine habitats in the EMR. These data represent enduring features which are elements of the physical environment that do not change considerably and they are known to influence the diversity of biological systems. This is important for marine conservation by contributing to the better definition and characterisation of benthic habitats. Seabed texture and composition are easily measurable parameters that when combined with other physical features can be used to create "seascapes" that serve as broad surrogates for benthic habitats and biota (Whiteway et al., 2007). Seascapes have the potential to be used in informing the marine bioregional planning process.