1. Blevin et al.:Hydrocarbon prospectivity of the Bight Basin - petroleum systems analysis in a frontier basin 2. Boreham et al : Geochemical Comparisons Between Asphaltites on the Southern Australian Margin and Cretaceous Source Rock Analogues 3. Brown et al: Anomalous Tectonic Subsidence of the Southern Australian Passive Margin: Response to Cretaceous Dynamic Topography or Differential Lithospheric Stretching? 4. Krassay and Totterdell : Seismic stratigraphy of a large, Cretaceous shelf-margin delta complex, offshore southern Australia 5. Ruble et al : Geochemistry and Charge History of a Palaeo-Oil Column: Jerboa-1, Eyre Sub-Basin, Great Australian Bight 6. Struckmeyer et al : Character, Maturity and Distribution of Potential Cretaceous Oil Source Rocks in the Ceduna Sub-Basin, Bight Basin, Great Australian Bight 7. Struckmeyer et al: The role of shale deformation and growth faulting in the Late Cretaceous evolution of the Bight Basin, offshore southern Australia 8. Totterdell et al : A new sequence framework for the Great Australian Bight: starting with a clean slate 9. Totterdell and Bradshaw : The structural framework and tectonic evolution of the Bight Basin 10. Totterdell and Krassay : The role of shale deformation and growth faulting in the Late Cretaceous evolution of the Bight Basin, offshore southern Australia

The rifted margins of eastern and southern Australia formed during multiple periods of extension associated with the fragmentation and dispersal of Gondwana in the Late Jurassic to Early Eocene (Veevers & Ettreim 1988; Veevers et al. 1991). The sedimentary basins of the Southern Rift System (Stagg et al. 1990) extend from Broken Ridge in the west, to the South Tasman Rise (STR) in the east. Collectively, these depocentres cover an area in excess of 1 million square kilometres (excluding the STR), with the thickest sediments (up to 15 km) occurring in the Ceduna Sub-basin of the Bight Basin. Early phases of the extension during the late Middle Jurassic to Early Cretaceous resulted in the formation of a series of west-northwesterly trending continental rift basins along the southern margin of Australia and a series of north-northwest trending transtensional basins along the western margin of Tasmania. The amount of upper crustal extension varied between basins of the rift system. This phase of upper crustal extension preceded eventual breakup between the Australian and Antarctic plates off the Bight Basin in the latest Santonian to earliest Campanian (Sayers et al. 2001). The nature of source rocks within the rift basins reflects the eastward propagation of the rift system through time, with largely terrestrial systems dominating in the early rift stages, followed by marine inundation from the Aptian onwards (west of the Otway Basin). In the Otway Basin, the first marine influence is recorded during the early Turonian, while in the Sorell and Bass basins marine conditions prevailed from ?Maastrichtian and middle Eocene time, respectively. Terrestrial progradational systems in the Late Cretaceous are important in the maturation of potential source rocks in the Bight and Otway basins, while Neogene carbonate-dominated systems are important in the Sorell, Bass and Gippsland basins. Outside of the Gippsland Basin where exploration has reached a mature status, the southern margin basins remain frontier to moderately exploration areas, with an overall drilling density (excluding the Gippsland Basin) of approximately 1 well per 6,000 square kilometres. Key Words: Australian Southern Margin, Southern Rift System, petroleum systems References SAYERS, J., SYMONDS, P.A., DIREEN, N.G. and BERNARDEL, G., 2001. Nature of the continent-ocean transition on the non-volcanic rifted margin of the central Great Australian Bight. In, Wilson, R.C.L., Whitmarsh, R.B., Taylor, B., and Froitzheim, N., (Eds), Non-Volcanic Rifting of Continental Margins; A Comparison of Evidence from Land and Sea. Geological Society, London, Special Publications, 187, 51?77. STAGG, H.M.J., COCKSHELL, C.D., WILLCOX, J.B., HILL, A., NEEDHAM, D.J.L., THOMAS, B., O?BRIEN, G.W. and HOUGH, P., 1990. Basins of the Great Australian Bight region, geology and petroleum potential. Bureau of Mineral Resources, Australia, Continental Margins Program Folio 5. VEEVERS, J.J. and ETTREIM, S.L., 1988. Reconstruction of Australia and Antarctica at breakup (95 ? 5 Ma) from magnetic and seismic data at the continental margin. Australian Journal of Earth Sciences, 35, 355?362. VEEVERS, J.J., POWELL, C.MCA. and ROOTS, S.R., 1991. Review of seafloor spreading around Australia, I. Synthesis of the patterns of spreading. Australian Journal of Earth Sciences, 38, 373?389. WILLCOX, J.B. and STAGG, H.M.J., 1990. Australia?s southern margin, a product of oblique extension. Tectonophysics, 173, 269?281.

The North Australian Basins Resource Evaluation was a multidisciplinary project. Its aim was to provide the mineral exploration industry with a predictive chronostratigraphic basin framework in northern Australia. The project was a collaborative venture of the Commonwealth, Queensland and Northern Territory Governments, funded under the National Geoscience Mapping Accord. Industry collaboration provided access to confidential drill core and regional geophysical datasets.

Palynological studies of Triassic-Jurassic well sections in the Offshore North Perth Basin have helped to reveal a more complicated geological history than previously recognised. This work is part of a major Geoscience Australia project studying the geological history and petroleum prospectivity of the basin. Seismic and well log interpretations have been combined with the sedimentological data to develop a high resolution sequence stratigraphic framework. This work is heavily reliant on the palynological data to provide the necessary age control, palaeoenvironmental interpretations and well correlations. Abstract continues (no space in field).

The Bight Basin in offshore southern Australia is one of the few remaining major frontier basins in the world. Following the initiation of sea-floor spreading between Australia and Antarctica in the late Santonian, a large deltaic system, known as the Hammerhead Delta, built out into the Ceduna Sub-basin. At the end of the Cretaceous the major influx of siliciclastic sediment ceased. Most of the area of the former delta has been subsequently dominated by marly sedimentation in relatively deepwater. The Hammerhead delta strata extend over an area of over 100,000 km2 and are up to 5000 m thick. Although the Hammerhead Delta built out on a continental margin, the strata have a number of marked differences to strata in well-documented late Cenozoic deltas that built out in such settings. There is a very limited progradation of the Upper Cretaceous shelf break in the Ceduna basin. Instead there is a high preservation of the delta topset strata which are composed predominantly of highstand system tracts with progradational and aggradational parasequence sets. Coal-bearing strata occur landward of the shoreface deposits. In places the parasequence stacking patterns result in large clinoform structures that are up to 700 m in amplitude. The scale of these clinoforms suggest the possibility that they were steep enough for the generation of turbidity currents and consequently there may well be some submarine fan deposits preserved at the base of the clinoforms, landward of the Upper Cretaceous shelf break.

A detailed sequence stratigraphic study has been undertaken on the three wells in the Houtman Sub-basin: Gun Island 1, Houtman 1 and Charon 1. The study focussed on the Early-Late Jurassic Cattamarra Coal Measures, Cadda Formation and Yarragadee Formation succession. Wireline log character, cuttings, sidewall core and conventional core lithologies and palynological data were used to identify facies and paleoenvironments. Palynology for all wells has been reviewed, including new data collected by Geoscience Australia for Gun Island 1. Facies stacking patterns were used to define systems tracts and subsequently ten third-order depositional sequences. At the second-order (supersequence) level, the Cattamarra Coal Measures record a transgression culminating in maximum flooding in the Cadda Formation followed by highstand aggradation and regression in the Yarragadee Formation. The third-order sequences characterised in this study overprint this supersequence and control the local distribution of facies. The relative dominance of a facies may be either enhanced or diminished depending upon its position within the larger second-order supersequence. For example, a number of transgressive systems tracts within the dominantly non-marine Yarragadee Formation and Cattamarra Coal Measures record multiple, dinocyst-bearing, minor marine incursions into the Houtman Sub-basin. These marine incursions are not evident in the Yarragadee Formation in Charon 1, indicating a lack of accommodation space or proximal sediment input in the north during the mid-late Jurassic. The combined influence of these third-order and second-order sequences on facies distribution has significant implications for the distribution of potential reservoirs and seals in the Houtman Sub-basin and for regional palaeogeographic reconstructions of the Perth Basin.

Geoscience Australia acquired seismic survey GA 310, in 2008-2009, across the southwest margin of Australia, as part of the Australian Government's Energy Security Program. Deep reflection seismic and potential field data were recorded across sparse 2D grids, located over the Wallaby Plateau in the north, Mentelle Basin in the south and the intervening Houtman and Zeewyck sub-basins of the northern Perth Basin. The offshore northern Perth Basin extends for some 700 km along the Western Australia margin, from the towns of Carnarvon in the north to Cervantes in the south. The largely Paleozoic-Mesozoic tectonostratigraphic framework is dominated by Permian and Early-Middle Jurassic rifting, followed by Late Jurassic-Early Cretaceous rifting leading to Valanginian breakup between Australia and Greater India. Underlying Precambrian Pinjarra Orogen structuring, in conjunction with rifting, has resulted in the development of several complex depocentres and basement highs. A recent re-evaluation of the offshore northern Perth Basin well-based lithostratigraphy into a new chronostratigraphic sequence framework has been carried outboard, over the GA 310 seismic lines, into the margin bounding Zeewyck and northern Houtman sub-basins. The main sequences hosting source rocks - Kockatea and Cattamarra - are widely present in the expansive northern Houtman Sub-basin, and are likely present in the deep Zeewyck Sub-basin. The mapping of a thick Late Jurassic Yarragadee Sequence within the Zeewyck Sub-basin indicates a major pre-breakup locus of relatively rapid deposition. The structural interpretation across the sub-basin highlights breakup-drift unconformities, strike-slip faulting and suggests a probable along-margin sheared crustal sliver - tectonic elements commensurate with an evolving rift-shear breakup margin.

Abstract for APPEA Conference presentation and journal publication

The conjugate margins of Wilkes Land, Antarctica, and the Great Australian Bight (GAB) are amongst the least understood continental margins. Break up along the GAB-Wilkes Land part of the Australian-Antarctic margin commenced at approximately 83 Ma. Using recent stratigraphic interpretations developed for the GAB, we have established a sequence stratigraphy for the Wilkes Land margin that will, for the first time, allow for a unified study of the conjugate margins. By reconstructing the two margins to their positions prior to break up we were able to identify comparable packages on the Wilkes Land margin to those recognised on the GAB margin. Excluding the glacial sediments on the Antarctic margin, the sedimentary sequence along the Wilkes Land margin is very thin compared to the GAB margin, which has substantially more syn- and post-rift sediments. Despite the differences in thickness, the syn-rift sedimentary package on the Wilkes Land margin exhibits a similar style of extensional faulting and seismic character to its GAB margin counterpart. In comparison, post-rift sequences on the Wilkes Land margin are markedly different in geometry and seismic character from those found on the GAB margin. Isopach mapping shows substantial differences in the thickness of the post-breakup sediments, suggesting different sediment sources for the two margins. The Late Cretaceous Hammerhead Supersequence provides much of the post-rift thickness for the GAB margin as a result of large sediment influx into the basin. This supersequence is characterised by thick progradational succession and was deposited in fluvio-deltaic and marine environments. The equivalent succession on the Wilkes Land margin has a different seismic character. It is thinner and aggradational, suggesting a distal marine environment of deposition.

Contents: 1. Lambert IB and Perkin DJ. Australia's mineral resources and their global status. 2. Davidson GJ and Large RR. Proterozoic copper-gold deposits. 3. Dorling SL, Groves DI and Muhling P. Lennard Shelf Mississippi Valley-type (MVT) Pb-Zn deposits, Western Australia. 4. Dowling SE and Hill RET. Komatiite-hosted nickel sulphide deposits, Australia. 5. Gemmell JB, Large RR and Khin Z. Palaeozoic volcanic-hosted massive sulphide deposits. 6. Hoatson DM. Platinum-group element mineralization in Australian Precambrian layered mafic-ultramafic intrusions. 7. Huston DL. The hydrothermal environment. 8. Jaques AL. Kimberlite and lamproite diamond pipes. 9. Kitto PA. Renison-style carbonate-replacement Sn deposits. 10. Lawrie KC and Hinman MC. Cobar-style polymetallic Au-Cu-Ag-Pb-Zn deposits. 11. McGoldrick P and Large RR. Proterozoic stratiform sediment-hosted Zn-Pb-Ag deposits. 12. Mernagh TP, Wyborn LAI and Jagodzinski EA. 'Unconformity related' U and/or Au and/or platinum-group-element deposits. 13. Morris RC. BIF-hosted iron ore deposits - Hamersley style. 14. Phillips GN and Hughes MJ. Victorian gold deposits. 15. Rowins SM, Groves DI and McNaughton NJ. Neoproterozoic Telfer-style Au (Cu) deposits. 16. Senior BR. Weathered-profile-hosted precious opal deposits. 17. Walters SG. Broken Hill-type deposits. 18. Waring CL, Heinrich CA and Wall VJ. Proterozoic metamorphic copper deposits. 19. Wilcock S. Sediment-hosted magnesite deposits. 20. Yeats CJ and Vanderhor F. Archaean lode-gold deposits. 21. Cooke DR and Large RR. Practical uses of chemical modelling - defining new exploration targets in sedimentary basins. 22. Idnurm M and Wyborn LAI. Palaeomagnetism and mineral exploration related studies in Australia: a brief overview of Proterozoic applications. 23. Krassay AA. Outcrop and drill core gamma-ray logging integrated with sequence stratigraphy: examples from Proterozoic sedimentary successions of northern Australia. 24. Waring CL, Andrew AS and Ewers GR. Use of O, C and S stable isotopes in regional mineral exploration. 25. Oliver NHS, Rubenach MJ and Valenta RK. Precambrian metamorphism, fluid flow, and metallogeny of Australia. 26. Taylor G and Butt CRM. The Australian regolith and mineral exploration. 27. Barley ME. Archaean volcanic-hosted massive sulphides. 28. Blevin P. Palaeozoic tin and/or tungsten deposits in eastern Australia. 29. Brand NW, Butt CRM and Elias M. Nickel laterites: classification and features. 30. Butt CRM. Supergene gold deposits. 31. Cooke DR, Heithersay PS, Wolfe R and Calderon AL. Australian and western Pacific porphyry Cu-Au deposits. <strong>Related information</strong> <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=63681">Blevin PL, Intrusion related gold deposits</a> *Not incuded in original AJGG text. Model first published here September 2005.