Abstract: The Collaborative East Antarctic Marine Census (CEAMARC) surveys to the Terre Adélie and George V shelf and margin highlight the requirement for a revised high resolution depth model that can be used as a spatial tool for improving physical models of the region. We have combined available shiptrack and multibeam bathymetry, coastline and land topographic data to develop a new high-resolution depth model, called GVdem. GVdem spans an area 138°E to 148°E longitude and 63°S to 69°S latitude, with a choice of three ESRI grids with cell pixel sizes: 15 arcsec, 9 arcsec and 3.6 arcsec. The revised depth model is an improvement over previously available regional-scale grids, and highlights seabed physiographic detail not previously observed for this part of East Antarctica. In particular, the extent and complexity of the inner-shelf depressions are revealed and their relationship with large shelf basins and adjacent flat-topped banks.

CAML is a five year International Program which will be undertaken as a major activity during the International Polar Year. This project will bring together all known data on Antarctic marine biodiversity and ocean change. The Antarctic Ocean is one of the most sensitive ecosystems in the world. Research undertaken via CAML will produce fascinating images of the Southern Ocean Geoscience Australia's Marine and Coastal Group is contributing expertise in sea floor mapping and sediment core collection to CAML. The Australian Government Antarctic Division is collecting oceanographic data, video footage and sediment cores through hot-water drill holes in the Amery Ice Shelf. The sediment cores are collected using a corer designed and built by Geoscience Australia, and are being analysed by scientists at Geoscience Australia to understand the environmental history beneath this ice shelf. This project has now produced four cores. The only other core ever obtained from beneath an extant ice shelf from under the Ross Ice Shelf in the early 1970s showed no signs of life. However, several Amery cores contain diatom-rich sediments, and one contains a succession of benthic faunas that indicate progressive colonisation of the sub-ice sea floor as ice retreated and currents began to seep nutrients and plankton into the sub-ice shelf cavity.

This paper presents tectonic elements maps for the continental margin of East Antarctica, from 38-164E, together with brief descriptions of all the major tectonic elements.

Geoscience Australia has recently conducted absolute gravity observations at Davis and Mawson stations in the Australian Antarctic Territory to establish accurate gravity reference points for past and future gravity surveys. These absolute gravity observations are the first such measurements undertaken at any of the Australian Antarctic stations and will not only provide an accurate absolute datum for future gravity work but will also enable gravity surveys that have already been conducted in the Australian Antarctic Territory to be tied to the same datum, thus allowing past and future gravity surveys to be accurately merged and combined.

Geoscience Australia has increased its capability on the Antarctic continent with the installation of Continuous Global Positioning System (CGPS) sites in the Prince Charles Mountains and Grove Mountains. Over the course of the 2006-07 Antarctic summer, Geoscience Australia and the Australian National University (ANU) installed new CGPS sites at the Bunger Hills and Richardson Lake and performed maintenance of the CGPS sites at the Grove Mountains, Wilson Bluff, Daltons Corner and Beaver Lake. The primary aim of the CGPS sites is to provide a reference frame for Antarctica, which is used to determine the long-term movement of the Antarctic plate. Data from Casey, Mawson and Davis is supplied to the International GPS Service (IGS) and in turn used in the derivation of the International Terrestrial Reference Frame (ITRF). The sites also open up opportunities for research into post-glacial rebound and plate tectonics. In addition, in the 2006-07 Antarctic summer a reconnaissance survey was undertaken at Syowa Station to determine whether a local tie survey could be performed on the Syowa VLBI antenna in the future. Upgrades were made to the Davis and Mawson CGPS stations and geodetic survey tasks such as reference mark surveys, tide gauge benchmark levelling and GPS surveys were performed at both Davis and Mawson stations. In addition, work requested by Geoscience Australia's Nuclear Monitoring Project, the Australian Government Antarctic Division (AGAD) and the University of Tasmania (UTAS) were completed.

Geoscience Australia's involvement in Antarctica has primarily been focused on the maintenance and enhancement of geodetic infrastructure within the Australian Antarctic Territory (AAT). Such infrastructure provides a fundamental reference frame for the region and supports earth monitoring science applications on local, regional and continental scales. These foundations have furthered the development of geodesy throughout the continent and provided information on the contemporary motion of the Antarctic plate for comparison with long-term geological records. Primary Antarctic geodetic control also contributes to a greater understanding of global earth movement though contribution to the International Terrestrial Reference Frame solutions. This report focuses on the field work undertaken during the 2010/11 Antarctic summer by Geoscience Australia surveyors at the Davis, Mawson and Macquarie Island research stations, as well as several remote sites in Eastern Antarctica. At each of the research stations, upgrades and local monitoring surveys were performed at the continuously operating reference stations (CORS), which form part of the Australian Regional GNSS Network and also contribute to the International GNSS Service. Remote GPS sites in the Grove Mountains, Bunger Hills, Wilson Bluff and Mt Creswell were also visited for equipment upgrades and data retrieval. Additional surveys were undertaken directed at enhancing the spatial infrastructure around both the Larsemann and Vestfold Hills. Support was also provided to a number of different Australian Antarctic Division projects.

The sediments deposited beneath the floating ice shelves around the Antarctic margin provide important clues regarding the nature of sub-ice shelf circulation and the imprint of ice sheet dynamics and marine incursions on the sedimentary record. Understanding the nature of sedimentary deposits beneath ice shelves is important for reconstructing the icesheet history from shelf sediments. In addition, down core records from beneath ice shelves can be used to understand the past dynamics of the ice sheet. Six sediment cores have been collected from beneath the Amery Ice Shelf in East Antarctica, at distances from the ice edge of between 100 and 300 km. The sediment cores collected beneath this ice shelf provide a record of deglaciation on the Prydz Bay shelf following the last glaciation. Diatoms and other microfossils preserved in the cores reveal the occurrence and strength of marine incursions beneath the ice shelf, and indicate the varying marine influence between regions of the sub-ice shelf environment. Variations in diatom species also reveal changes in sea ice conditions in Prydz Bay during the deglaciation. Grain size analysis indicates the varying proximity to the grounding line through the deglaciation, and the timing of ice sheet retreat across the shelf based on 14C dating of the cores. Two of the cores contain evidence of cross-bedding towards the base of the core. These cross-beds most likely reflect tidal pumping at the base of the ice shelf at a time when these sites were close to the grounding line of the Lambert Glacier.

Frank Stillwell was a member of Douglas Mawson's 1911-1914 expedition to Cape Denison, Commonwealth Bay, Antarctica. His 1912 diary is being edited for publication. The editor has asked for a text box to be included in the publication that describes aspects of the geomagnetism activities that formed part of the expedition's scientific program.

During 2005 Geoscience Australia operated geomagnetic observatories at Kakadu and Alice Springs in the Northern Territory; Charters Towers in Queensland; Learmonth and Gnangara in Western Australia; Canberra in the Australian Capital Territory; Macquarie Island, Tasmania, in the sub-Antarctic; and Casey and Mawson in the Australian Antarctic Territory. Three geomagnetic repeat stations were also occupied in 2005. The Australian Geomagnetism Report 2005 (Volume 53) describes instrumentation and activities; absolute reference magnetometers; data distribution; and presents monthly and annual mean magnetic values, plots of hourly mean magnetic values and K indices at the magnetic observatories and repeat stations operated by Geoscience Australia during calendar year 2005.

Less than one year after the spectacular calving of the Mertz Glacier tongue, scientists were collecting the first ever images of the seafloor where the glacier tongue once sat.