Record 2015/24 | GeoCat 79136
Seabed environments, shallow sub‑surface geology and connectivity, Petrel Sub-basin, Bonaparte Basin, Timor Sea Interpretative report from marine survey GA0335/SOL5463 Nicholas, W. A., Carroll, A., Picard, K., Radke, L., Siwabessy, J., Chen, J., Howard, F. J. F., Dulfer, H., Tran, M., Consoli, C., Przeslawski, R., Li, J., Jones, L. E. A.
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Seabed environments, shallow sub-surface geology and connectivity, Petrel Sub-basin, Bonaparte Basin, Timor Sea Interpretative report from marine survey GA0335/SOL5463 GEOSCIENCE AUSTRALIA RECORD 2015/24
Nicholas, W. A., Carroll, A., Picard, K., Radke, L., Siwabessy, J., Chen, J., Howard, F. J. F., Dulfer, H., Tran, M., Consoli, C., Przeslawski, R., Li, J., Jones, L. E. A.
Department of Industry, Innovation and Science Minister for Resources, Energy and Northern Australia: The Hon Josh Frydenberg MP Assistant Minister for Science: The Hon Karen Andrews MP Secretary: Ms Glenys Beauchamp PSM Geoscience Australia Chief Executive Officer: Dr Chris Pigram This paper is published with the permission of the CEO, Geoscience Australia
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[email protected]. ISSN 2201-702X (PDF) ISBN 978-1-925124-85-9 (PDF) GeoCat 79136 Bibliographic reference: Nicholas, W.A., Carroll, A., Picard, K., Radke, L., Siwabessy, J., Chen, J., Howard, F.J.F., Dulfer, H., Tran, M., Consoli, C., Przeslawski, R., Li, J. & Jones, L.E.A. 2015. Seabed environments, shallow sub-surface geology and connectivity, Petrel Sub-basin, Bonaparte Basin, Timor Sea: Interpretative report from marine survey GA0335/SOL5463. Record 2015/24. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2015.024
Contents Executive Summary..................................................................................................................................1 1 Introduction ............................................................................................................................................3 1.1 Scope and aims ...............................................................................................................................3 1.1.1 Survey area and outline of this report ........................................................................................6 2 Setting....................................................................................................................................................7 2.1 Regional geology .............................................................................................................................7 2.2 Flat Top 1 well ..................................................................................................................................7 2.3 Modern marine environments ........................................................................................................11 2.4 Evolution of the Quaternary Bonaparte Shelf ................................................................................12 2.5 Regional evidence of hydrocarbon seepage .................................................................................15 2.6 Evidence of seepage within the Petrel Sub-basin .........................................................................15 3 Methods ...............................................................................................................................................18 3.1 Overview ........................................................................................................................................18 3.1.1 Geomorphic feature mapping ...................................................................................................18 3.1.2 Pockmark identification and mapping ......................................................................................19 3.1.3 Relationships among backscatter, hardness and pockmarks ..................................................19 3.1.4 Sedimentology ..........................................................................................................................20 3.1.5 Seabed sediment geochemistry ...............................................................................................20 3.1.6 Isotopic composition of carbonates ..........................................................................................21 3.1.7 Headspace gas and organic soluble matter compounds .........................................................21 3.2 Ecological analyses .......................................................................................................................22 3.2.1 Biological analyses ...................................................................................................................22 3.2.2 Towed underwater imagery ......................................................................................................22 3.2.3 Mollusc identification ................................................................................................................22 3.3 Radiocarbon dating ........................................................................................................................23 3.4 Acoustic sub-bottom profiles ..........................................................................................................23 4 Results: Seabed properties, geomorphology and habitats .................................................................24 4.1 Seabed geomorphology and sediments of Area 1 ........................................................................24 4.1.1 Geomorphology ........................................................................................................................24 4.1.2 Relationships between seabed features and acoustic hardness .............................................28 4.1.3 Surface sediment composition and texture ..............................................................................32 4.1.4 Vibrocore sediments (
