Metadata record for data from ASAC Project 933 See the link below for public details on this project. Australian Antarctic and Southern Ocean Profiling Project (AASOPP) was the outcome of a government decision in 1999 that it would carry out the necessary work to place Australia in a position to be able to prepare a submission defining the outer limit the 'extended Continental Shelf' (ECS) off the Australian Antarctic Territory (AAT). The ECS is the area of seabed/subsoil jurisdiction extending beyond the 200 nautical mile Exclusive Economic Zone, and is defined by Article 76 of the United Nations Convention on the Law of the Sea. AASOPP was set up in 2000, under the management of the Department of Finance and Administration and in consultation with the Australian Antarctic Division, to undertake the acquisition and interpretation of the data that would underpin a UN submission. Technical aspects of the work were largely the responsibility of the Australian Geological Survey Organisation and the Australian Surveying and Land Information Group (later Geoscience Australia). Marine geophysical surveys were conducted in 2001/2 and 2002/3 by the primary contractors, FUGRO Geoteam supervised by AGSO (Geoscience Australia) using the vessels Geoarctic and Polar Duke (survey numbers GA227, GA228 and GA229). Data collected were seismic reflection, sonobuoy seismic refraction, magnetic and gravity profiles. Data processing was supervised by Geoscience Australia where they are archived. Seismic data were lodged with the SCAR Seismic Data Library. Law of the Sea interpretations were lodged as part of the Australian submission to the United Nations by November, 2004 with a request not to examine the Antarctic case until requested.

A collaborative Italian/Australian marine geoscience research voyage to the George Vth Land sector of the East Antarctic continental margin was carried out between 11th February and 20th March, 2000, on board the of the RV Tangaroa. The cost of the expedition was shared jointly by the Italian and Australian National Antarctic Research Programs. Twenty four scientific personnel from 13 institutions participated in the expedition. The geophysical data collected includes a total of 1827 km of multi-channel seismic data and 562 km of Chirper sonar data. A total of 11 gravity cores, 28 piston cores, 18 surface grabs and 11 short trigger cores were collected on the voyage. Water profile (CTD) measurements and water samples were collected at nine stations and seabed bottom photographs were made at 11 stations. The expedition discovered and mapped a shelf sediment drift deposit covering about 400 km2 lying in an greater than 800m deep section of the George Vth basin west of the Mertz Glacier. It is a true 'drift' deposit, since these sediments exhibit a patchy distribution, large-scale bedforms, contain foreset bedding and display a depositional architecture indicative of contour-parallel sediment transport. A significant observation is that the drift thins to the north into an acoustically-transparent veneer; this observation implies that the drift is sourced from the outer continental shelf, with sediment being transported landwards, across the shelf and into an 850m deep inner shelf basin. The 'Mertz Drift' is over 35 m thick and core samples demonstrate that it is composed of laminated, anoxic, gelatinous olive green, silicious mud and diatom ooze (SMO). Preliminary shipboard counts of the laminae suggest a thickness of from 4 to 20mm, with a mean of about 7mm. While the lower sediments are laminated, there is a 20 to 50cm thick sandy drape at the surface over the whole of the drift. This suggests that a recent (late Holocene) change in the depositional environment has occurred, possibly related to changes in the extent of the nearby Mertz Glacier tongue, current regime and/or to the persistence of sea ice over the shelf area. Multi-channel seismic data show the occurrence of foreset beds at the shelf break, interpreted as having been deposited by ice streams that grounded on the outer shelf during glacial maxima. On the shelf, the seismic character of the seafloor exhibits highly reflective, parabolic reflectors suggestive of crystalline basement, cropping out at the seafloor. Northwards of these basement outcrops, the water depth increases to over 1,100 m which is the George Vth Basin. The basin coincides with an abrupt transition in seismic character from acoustic basement in the south to seaward (northeasterly) dipping reflectors. On the continental rise, seismic sections were taken across a contourite drift deposit and submarine canyon system in 2500 to 3500 m water depth. Piston cores were collected along the profile of one drift deposit which gave a preliminary Mid-Pliocene age to truncated strata that crop out on the drift's steeper lee side. These data will provide useful site-survey information in support of a proposal sent to the Ocean Drilling Program under the auspices of the SCAR-ANTOSTRAT project for drilling key sites along the Antarctic margin.

This metadata record is a modified child record of an original parent record originating from custodians of data associated with Geoscience Australia (The identifier of the parent record is ANZCW0703006701, and can be found on the Australian Spatial Data Directory website - see the URL given below). A bathymetric grid of the Macquarie Island Region (Longitudes 151 E and 167 E, Latitudes 48 S and 62 S) was produced. In doing so, the individual datasets used were closely examined and any deficiencies noted for further follow up or were rectified immediately and the changes documented. These datasets include modern multibeam data, coastline data obtained from georeferenced SPOT imagery, hydrographic quality data, echosounder data from research and fishing vessels and satellite derived bathymetric data. A hierarchical system was employed whereby the best and most extensive datasets were gridded first and applied as a mask to the next best dataset. A new masking grid would be formed from these datasets to pass non-overlapping data in the next best dataset. This procedure was employed until finally the satellite data were masked. All the various levels of masked data were then brought together by the gridding algorithm (Intrepid and Desmond Fitzgerald Associates) and an ERMapper format grid produced. A grid cell size of 0.00225 (nominal 250m) was used with many iterations of minimum curvature gridding and several passes of smoothing. The final grid is available in geotiff, ArcInfo ascii and xyz text formats. A detailed report of the work completed is also available.

This metadata record is a modified child record of an original parent record originating from custodians of data associated with Geoscience Australia (The identifier of the parent record is ANZCW0703009248, and can be found on the Australian Spatial Data Directory website - see the URL given below). Taken from the report: A bathymetric grid of the Heard Island-Kerguelen Plateau Region (Longitudes 68 degrees E - 80 degrees E, Latitudes 48 degrees S - 56 degrees S) is produced. In doing so, the individual datasets used have been closely examined and any deficiencies noted for further follow up or have been rectified immediately and the changes documented. These datasets include modern multibeam data, coastline data obtained from the World Vector Shoreline, echosounder data from research, fishing and Customs vessels and satellite derived bathymetric data. A hierarchical system was employed whereby the best and most extensive datasets were gridded first and applied as a mask to the next best dataset. A new masking grid would be formed from these datasets to pass non-overlapping data in the next best dataset. This procedure was employed until finally the satellite data were masked. All the various levels of masked data were then brought together by the gridding algorithm (Intrepid - Desmond Fitzgerald Associates) and an ERMapper format grid produced. A grid cell size of 0.005 degrees (nominal 500m) was used with many iterations of minimum curvature gridding and several passes of smoothing. The final grid is available in ERMapper, ArcInfo and ASCII xyz formats.

The Australian Antarctic Division (AAD) has developed a proposal for the establishment of seven Marine Protected Areas (MPAs) located around east Antarctica for the purposes of marine ecosystem conservation. As seafloor morphology is a key component of marine ecosystems, this bathymetry compilation for the proposed MPAs was produced to support the AAD proposal. All bathymetry data available to Geoscience Australia at the time of compilation were used. This included multibeam and singlebeam acoustic data which were verified and processed to ensure the data were as accurate as possible. Processing included sound velocity corrections, navigation verification and the rejection of erroneous data points. Once processed, the data were gridded to 100m resolution and projected into suitable WGS84 UTM zones. The gridded data was exported into several formats to facilitate ease of use. The formats include xyz files, ESRI rasters, geoTIFs, CARISTM image files and soundings. The data and the technical report are available for download from URLs below.