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  • Multichannel seismic data collected off Wilkes Land (East Antarctica) reveal four main units that represent distinct phases in the evolution of the Cenozoic depositional environment. A Cretaceous synrift succession is overlain by hemipelagic and distal terrigenous sequences deposited during Phase 1. Sediment ridges and debris-flow deposits mark the transition to Phase 2. Unit 3 records the maximum sediment input from the continent and is characterized by the predominance of turbidite deposits. During Phase 4 the sediment supply from the continental margin was reduced, and draping and filling were the dominant processes on the continental rise. Unit 4 also contains the deposits of sediment wave fields and asymmetric channel-levee systems. These four units are a response to the Cenozoic evolution of the East Antarctic Ice Sheet. During Phase 1, small ice caps were formed in the innermost continental areas. The ice volume increased under temperate glacial regimes during Phases 2 and 3, when large volumes of melt-water production led to high sediment discharge to the continental rise. Change to a polar regime occurred through Phase 4, when a thick prograding wedge developed on the continental shelf and slope and the sediment transport to the rise diminished, producing general starvation conditions.

  • To study the seafloor morpholofy on the George V land shelf, East Antarctica, over 2000 kilometres of high-frequency echo-sounder data were collected between February and March 2000. The acoustic facies are explained in terms of glacial and oceanographic influences on the shelf since the Last Glacial Maximum.

  • The Antarctic continental slope spans the depths from the shelf break (usually between 500-1000 m) to ~3000 m, is very steep, overlain by 'warm' Circumpolar Deep Water and life there is poorly studied. This study investigates whether life on Antarctica's continental slope is essentially an extension of the shelf or the deep-sea fauna, a transition zone between these or clearly distinct in its own right. Using data from several cruises to the Weddell and Scotia sea, including the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) I-III and BIOPEARL (BIOdiversity, Phylogeny, Evolution and Adaptive Radiation of Life in Antarctica) 1 and EASIZ II cruises as well as current data bases (SOMBASE, SCAR-MarBIN), we selected four different taxa (i.e. cheilostome bryozoans, isopod and ostracod crustaceans, and echinoid echinoderms) and two areas, the Weddell and the Scotia Sea, to examine faunal composition, richness and affinities. The answer has important ramifications to the link between physical oceanography and ecology, and the potential of the slope to act as a refuge and resupply zone to the shelf during glaciations (and therefore support or not glaciological reconstructions of ice sheets covering continental shelves).

  • With improving accessibility to Antarctica, the need for proactive protection and management of sites of intrinsic scientific, historic, aesthetic or wilderness value is becoming increasingly important. Environmental protection and conservation practise in the Antarctic is globally unique and is managed by provisions contained within the Antarctic Treaty. Whilst these provisions have been primarily utilised to protect sites of biological or cultural significance, sites of geological or geomorphological significance may also be considered. However, in general, sites of geological and geomorphological significance are underrepresented in conservation globally, and, particularly, in Antarctica. Wider recognition of sites of geological significance in Antarctica can be achieved by development of a geo-conservation register, similar to geological themed inventories developed elsewhere in the world, to promote and recognise intrinsically valuable geological and geomorphological sites. Features on the register that are especially fragile, or otherwise likely to be disturbed, threatened or become vulnerable by human activity, can be identified as such and area management protocols for conservation, under the Antarctic Treaty, can be more readily invoked, developed and substantiated. Area management should mitigate casual souveniring, oversampling and accidental or deliberate damage caused by ill-advised construction or other human activity. The recognition of significant geological and geomorphological features within the Antarctic, and their protection, is identified under the current Australian Antarctic Science Strategic plan (under Stream 2.2; Vulnerability and spatial protection)

  • Numerical models are the primary predictive tools for understanding the dynamic behavior of the Antarctic ice sheet. But a key boundary parameter - the magnitude of sub-glacial heat flow - is controlled by geological factors and remains poorly constrained. We show that variations in the abundance and distribution of heat producing elements (U, Th and K) within the Antarctic continental crust give rise to regional sub-glacial heat flows as much as 2-3 times greater than previously assumed in ice modeling studies. We also recognize that, prior to the breakup of Gondwana, much of the East Antarctic continental crust was contiguous with southern Australia where extensive high-heat producing Proterozoic-aged rocks, and correspondingly elevated regional heat flows, are well documented. Such crustal rocks almost certainly extend beneath the modern east Antarctic ice sheet. This means that high sub-glacial heat flows are likely to be a regional phenomenon. Such fundamental geological controls on sub-glacial heat flow must be considered in accurately modelling ice dynamics, permitting more refined predictions of ice mass balance and sea level change.

  • Data from surveys along the East Antarctic margin will be presented to provide insights into the diversity and distribution of benthic communities on the continental shelf and slope, and their relationship to physical processes. Seabed video and still imagery collected from the George V shelf and slope and the sub-ice shelf environment of the Amery Ice Shelf indicate that the benthic communities in these regions are highly diverse, and are strongly associated with the physical environment. Variations in seafloor morphology, depth, sediment type and bottom circulation create distinct seabed habitats, such as muddy basins, rugged slope canyons and scoured sandy shelf banks, which are, in turn, inhabited by discrete seabed communities. The infauna dominated muddy basins contrast sharply with the diverse range of filter-feeding communities that occur in productive canyons and rugged inner shelf banks and channels. In the sub-ice shelf environment, differences in organic supply, linked to the circulation patterns, cause distinct differences in the seabed communities. The strong association between benthic communities and seafloor characteristics allows physical parameters to be used to extend our knowledge of the nature of benthic habitats into areas with little or no biological data. Comprehensive biological surveys of benthic communities in the East Antarctic region are sparse, while physical datasets for bathymetry, morphology and sediment composition are considerably more extensive. Physical data compiled within the proposed network of East Antarctic Marine Protected Areas (MPAs) is used to aid our understanding of the nature of the benthic communities. The diversity of physical environments within the proposed MPAs suggests that they likely support a diverse range of benthic communities.

  • We present calculated radiogenic crustal heat production values (ca. 1500 determinations) from available geochemical data (from OZCHEM, published literature and unpublished data) from exposed outcrops from the Australian Antarctic Territory (AAT). Geothermal heat production is derived from the radiogenic decay of the radioactive elements, primarily, U, Th and K, elements that are primarily concentrated in the earth's crust. In this report, we briefly assess the magnitude and heterogeneity of crustal heat production across the major regions within AAT. This information has been compiled as a foundation for subsequent, more comprehensive, geothermal heat assessments of the AAT (including heat flow, and thermal conductivity determinations) for the purposes of ice sheet modelling studies addressing the dynamic behaviour of the east Antarctic Ice Sheet.

  • From February to March 2010, Geoscience Australia (GA) conducted an multibeam survey of the coastal waters of the Vestfold Hills in the Australian Antarctic Territory. The survey was conducted jointly with Australian Antarctic Division (AAD) and the Deployable Geospatial Survey Team (DGST) of the Royal Australian Navy. The survey was aimed primarily at understanding the the character of the sea floora round Davis to better inform studies of the benthic biota and the possible impacts of the Davis Station sewage outfall. DGST were involved so the data could be used to update and extend the nautical charts of the Davis area.

  • Palaeogeographic reconstructions of the Australian and Antarctic margins based on matching basement structures are commonly difficult to reconcile with those derived from ocean floor magnetic anomalies and plate vectors. Following identification of a previously unmapped crustal-scale structure in the southern part of the Delamerian Orogen (Coorong Shear Zone), a revised plate reconstruction for these margins is proposed. This reconstruction positions the Coorong Shear Zone opposite the Mertz Shear Zone and indicates that structural inheritance had a profound influence on the location and geometry of continental breakup, and ocean fracture development. Previously, the Mertz Shear Zone has been correlated with the Proterozoic Kalinjala Mylonite Zone in the Gawler craton but this means that Australia is positioned 300-400 km too far east relative to Antarctica prior to breakup. Differences in the orientation of late Jurassic-Cretaceous basin-bounding normal faults in the Bight and Otway basins further suggest that extensional strain during basin formation was partitioned across the Coorong Shear Zone following an earlier episode of strike-slip faulting on a northwest-striking continental transform fault (Trans-Antarctic Shear).

  • The main objectives of the 2000 geodetic survey of Heard Island were to upgrade and extend the existing geodetic survey network to give a better coverage of the island and to establish accurate, globally compatible coordinates for all spatial data applications on the Island. In addition, GPS observations would provide information for the long-term measurement of horizontal and vertical movement. In the long term, these fundamental positions will provide information on the contemporary motion of Heard Island for comparison with geological records, with special emphasis on the Australia-Antarctic separation and the mid ocean ridge. In the meantime they provide a consistent and globally compatible spatial framework for all other studies on the Island. This report documents the methods and results of these surveys.