Authors / CoAuthors
Carroll, A.G. | Przeslawski, R.
Abstract
Geoscience Australia conducted a marine survey (GA0345/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 CO2Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The data collected during this survey complement sequence stratigraphic studies in the Caswell Sub-basin that provide constraints on the most suitable areas for storage of CO2 and help to identify potential CO2 storage reservoirs. The results of this work are published in GA Record 2015/XX (Geocat 83120). 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. Pre-survey site selection was informed by mapping fault networks and potential fluid-flow pathways connecting the regional seal to the seabed over interpreted CO2 storage play fairways and through interpretation of associated amplitude anomalies in 2D and 3D seismic data. Shipboard data 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 104 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 30 km2, along with 107 line km of side scan sonar, underwater camera and sub-bottom profile data. Eighteen Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, four grabs and one core. Shipboard and AUV multibeam bathymetry and sub-bottom profiler data indicated the presence of recently active faults in the area, some with significant seafloor surface expression (i.e. fault scarps with up to 40m offset). Some of these faults were visually inspected by the ROV which also confirmed the presence of diverse biological communities. Possible indications of shallow gas were observed on sub-bottom profiles, including amplitude anomalies, cross-cutting reflectors and zones of signal starvation. Water column observations including sidescan sonar, single-beam and multibeam echosounders, underwater video and photography did not conclusively identify hydrocarbon or other fluid seepage. Strong currents encountered during parts of the survey may have interfered with the direct detection of seeps in the water column. While no active signs of seepage were observed, the geochemical and biological sampling undertaken will aid in baseline environmental investigations for this region.
Product Type
dataset
eCat Id
83725
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
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2601
Australia
Keywords
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- Marine Data
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2015-01-01T00:00:00
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