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  • Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to sediment oxygen demand measurements undertaken on seabed sediments (0-2 cm).

  • Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to chlorophyll a, b, c and phaeophytin a conentrations in the upper 2 cm of seabed sediments.

  • Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to porosity, total chlorin and chlorin index data from the upper 2 cm of seabed sediments.

  • The Petrel Sub-basin Marine Survey (GA0335/SOL5463) was undertaken in May 2012 by Geoscience Australia in collaboration with the Australian Institute of Marine Science (AIMS), as part of the Australian Government's National Low Emission Coal Initiative (NLECI). Its purpose was to acquire pre-competitive geophysical and biophysical data on shallow seabed environments within two targeted areas to support assessment of CO2 storage potential. The geophysical acquisition consisted of multibeam sonar mapping of sea floor morphology and multi-channel sub bottom profiling of the shallow sub surface geology. The aim of sub bottom profiling was to investigate regional seal breaches and potential fluid pathways by providing high resolution images connecting the sea floor map to regional seismic reflection data acquired concurrently in the area. The sub bottom profiler data were acquired aboard the AIMS research vessel (RV) Solander along 51 lines, totalling 654 line km in the Petrel Sub-basin of the Bonaparte Basin. Acquisition employed a Squid 2000 sparker as the source and a 24 channel Microeel streamer for the receivers. Group interval was 3.125 m and shot interval 6.25 m, resulting in 6 fold data. Record length was 500 ms with a sample interval of 0.25 ms. Some problems in acquisition needed to be addressed in processing. Firstly, sea conditions were far from smooth for most of the voyage. Obvious relative motion occurred between the source and the streamer, and along the streamer itself, due to the ocean swell. In some cases, acquisition commenced while the vessel was still turning onto the line and the streamer was not straight in line behind the stern. Finally, malfunction of the sparker on some half dozen lines resulted in gaps in the coverage, which could not be filled in later, due to bad weather reducing the time for the survey. Multichannel seismic reflection processing was able to compensate for some of the limitations of sparker acquisition. Mutes and filters were necessary to remove the worst of the noise, including leaked timing pulse and swell noise. Surface related multiple elimination (SRME) successfully attenuated the water bottom and later multiples. Non surface consistent trim statics were able to correct for the relative motion of the sparker and the streamer, thereby allowing alignment of reflections prior to stack, which improved the signal to noise. Minimum entropy deconvolution was a critical step in both suppressing ghosting and enhancing latent high frequencies in the data, thus improving the resolution. Migration was necessary to correctly image small channels by collapsing diffractions. Finally tidal static corrections were essential to remove mis-ties in high frequency data. The processing stream has been well documented, along with scripts employed to handle the large amount of data efficiently and consistently. This record is a manual for a much more rigorous way of processing multi-channel sparker data, and details a work flow that can be implemented within Geoscience Australia and used for future surveys. The final migrated seismic data proved to be very high resolution, allowing delineation of multiple episodes of channelling in the top 100 m of sediment. Comparison of the sub bottom profiles with older regional seismic reflection data showed just how much more detail is available in the region critical for mapping deeper faults and fluid pathways to features on the sea floor. Acquisition and processing of the sub bottom profiler data surpassed the survey expectations.

  • Please note: This product has been superseded by 50m Multibeam Dataset of Australia 2018. - This tile contains all multibeam data held by Geoscience Australia on August 2012 within the specified area. The data has been gridded to 50m resolution. Some deeper data has also been interpolated within the mapped area. The image provided can be viewed on the free software CARIS Easyview, available from the CARIS website: www.caris.com under Free Downloads.

  • Please note: This product has been superseded by 50m Multibeam Dataset of Australia 2018. - This tile contains all multibeam data held by Geoscience Australia on August 2012 within the specified area. The data has been gridded to 50m resolution. Some deeper data has also been interpolated within the mapped area. The image provided can be viewed on the free software CARIS Easyview, available from the CARIS website: www.caris.com under Free Downloads.

  • Please note: This product has been superseded by 50m Multibeam Dataset of Australia 2018. - This tile contains all multibeam data held by Geoscience Australia on August 2012 within the specified area. The data has been gridded to 50m resolution. Some deeper data has also been interpolated within the mapped area. The image provided can be viewed on the free software CARIS Easyview, available from the CARIS website: www.caris.com under Free Downloads.

  • Please note: This product has been superseded by 50m Multibeam Dataset of Australia 2018. - This tile contains all multibeam data held by Geoscience Australia on August 2012 within the specified area. The data has been gridded to 50m resolution. Some deeper data has also been interpolated within the mapped area. The image provided can be viewed on the free software CARIS Easyview, available from the CARIS website: www.caris.com under Free Downloads.

  • Please note: This product has been superseded by 50m Multibeam Dataset of Australia 2018. - This tile contains all multibeam data held by Geoscience Australia on August 2012 within the specified area. The data has been gridded to 50m resolution. Some deeper data has also been interpolated within the mapped area. The image provided can be viewed on the free software CARIS Easyview, available from the CARIS website: www.caris.com under Free Downloads.

  • Surveying of nearshore areas in the Vestfold Hills using high resolution multibeam swath bathymetry provides both a detailed digital bathymetric model and information on sediment acoustic backscatter. Combined with underwater video transects and sediment sampling, these data can be used to identify and map geomorphic units. Six geomorphic units identified in the survey region include: Rocky outcrops, sediment-floored basins, pediments, steep-sided valleys, scarps and sheltered embayments. In addition to geomorphic units, the data reveal sedimentary structures that provide insights into sediment transport and erosion in the area. Ice keel pits and scours are common while seafloor channels, scour depressions and sand ribbons indicate transport and deposition by wind-driven currents and oceanographic circulation. Gullies and sediment lobes on steep slopes indicate mass movement of sediment. The sheltered embayments preserve a mantle of boulder sand probably deposited by cold-based glaciers. Automated techniques utilizing the bathymetric grid and backscatter to map landforms are useful in defining reproducible boundaries between geomorphic units but cannot easily be adapted to accurately classify the variations in sea floor texture and structure imaged by these data.