Measured sections and sequence stratigraphic interpretations of the Upper McNamara and Fickling Groups, Queensland.

Paleoproterozoic-earliest Mesoproterozoic sequences in the Mount Isa region of northern Australia preserve a 200 Myr record of intracontinental rifting and consequent passive margin formation. Passive margin formation followed a switch in the extensional direction from ENE-WSW to NE-SW ca. 1740 Ma, and was accompanied by extensional unroofing of 1670 Ma magmatic rocks from mid-crustal depths. The resulting asymmetries in basin geometry and crustal architecture represent a first-order constraint on reconstructions of Rodinia that juxtapose Proterozoic eastern Australia against rocks of comparable age in western Laurentia.

A new tectonostratigraphic framework for the southern Bowen, Gunnedah and Surat basins in New South Wales is developed, based on the sequence stratigraphic and structural interpretation of regional reflection seismic data, and petroleum and stratigraphic wells. This framework provides an improved correlation between the Bowen and Gunnedah basins, and delineates the relationship between tectonic events, basin phases, and the development of depositional sequences. The Early Permian Cretaceous depositional history of the basins in this region was controlled by successive phases of tectonic subsidence driven by extension, thermal relaxation and lithospheric flexure, interrupted by periods of contraction and uplift. Early Permian extension was characterised by the eruption of volcanic rocks and the accumulation of dominantly lacustrine sediments, followed by the deposition of thick coal-conglomerate successions, particularly along the eastern margin of the basin. The succeeding thermal subsidence phase was quickly overwhelmed by flexural subsidence driven by foreland loading during the Early Late Permian, and the deposition of marine, deltaic and non-marine rocks. Late Permian contraction and uplift in the Gunnedah Basin was followed by the accumulation of non-marine Triassic rocks derived from the New England Orogen. A dominantly fluvial Middle Triassic succession is present across the entire region. Effects of the Middle Late Triassic contractional event that is evident throughout the Bowen Gunnedah Sydney basin system were concentrated along the basin-bounding Goondiwindi, Kelvin and Mooki faults and also adjacent to the Boggabri Ridge

The principles of non-marine sequence stratigraphy were applied to the Jurassic strata in the lower part of the Surat Basin, in order to better determine the depositional history of the basin and highlight potential reservoir and source rocks. The lithostratigraphic units in the Early Late Jurassic interval can be divided into three supersequences: J, K, and L. Each supersequence consists of a basal sandstone-dominated unit generally exhibiting an unconformable, diachronous relationship with the underlying unit. This is the lowstand system tract (LST), which potentially offers an extensive well-sorted sandstone reservoir with interconnected porosity. These amalgamated sandstone sheets are overlain by a fining-upward interval consisting of predominantly muddier carbonaceous lithologies including coal and lacustrine deposits. This upper sequence embraces the transgressive system tract (TST) and possibly the highstand system tract (HST). Isolated meander-belt sandstone bodies may be preserved within these widespread finer deposits and provide reservoirs juxtaposed to source rocks. Vitrinite reflectance values indicate that these Jurassic units are immature to marginally mature and, hence, may only have limited hydrocarbon generating prospects

Paleoproterozoic sedimentary rocks of northern Australia host one of the world's most important zinc repositories. Despite more than fifty years of geological investigation, including the production of 1:250,000 and 1:100,000 geological maps and the drilling of countless mineral exploration holes public domain datasets contain comparatively little measured section and basic sedimentological information. Because these datasets are essential for understanding sediment architecture and basin shape they from a necessary stepping stone to formulating models aimed at constraining the flow of mineralising fluids in these basins. This data record provides the mineral exploration industry, university and government geoscientists with 37 single sections which are subsequently combined to form twenty six composite outcrop and drill core stratigraphic sections through the Surprise Creek Formation, Warrina Park and Torpedo Creek Quartzites, lower Gunpowder Creek Formation and Moondarra Siltstone. Close to twenty three thousand meters of stratigraphic/sedimentological description and interpretation are provided. Most sections contain grain size, lithology, bed thickness, sedimentary structure and gamma ray data from which facies and sequence stratigraphic surfaces are interpreted. Gamma ray data is not available for drill holes Templeton 1 and UD784. The section at Fiery Creek is generalised from the earlier work of researchers at Monash University and does not contain the detailed sedimentological information found in the rest of the logs. Eight sections contain revised interpretations from the earlier NABRE work. Despite the absence of invertebrate fossils the sequence interpretations, in combination with SHRIMP zircon ages and Apparent Polar Wander Path data, permit the erection of a well-constrained chronostratigraphic framework for these Paleoproterozoic rocks. Previous lithostratigraphic subdivisions were diachronous and emphasised local stratigraphic successions rather than basin-wide correlations. The data contained in this Geoscience Australia record and the earlier companion data releases of AGSO Records 1999/10, 1999/15 1999/19 and 2000/03 contain chronostratigraphic sequence subdivisions from which original basin shape and sediment architecture can be derived. Lithostratigraphic miscorrelations associated with quartzite sandbodies of the Warrina Park and Torpedo Creek Quartzites, unit Prc of the Surprise Creek Formation and the lower parts of the Gunpowder Creek Formation and Moondarra Siltstone are resolved. Detailed descriptions and discussions of facies, SHRIMP Zircon ages, lithostratigraphic miscorrelations and rationale for sequence stratigraphic interpretations are provided in Jackson et al., (in prep).

This Record presents a new stratigraphic interpretation of Cretaceous sedimentary rocks encountered in petroleum exploration wells, stratigraphic holes and water bores along the southern Australian coast in Western Australia and South Australia. The Cretaceous succession in these wells is interpreted within the Bight Basin sequence stratigraphic framework, and is correlated with the thicker section farther basinward. The correlation is based on existing and recently commissioned biostratigraphic data, and the interpretation of seismic data on the continental shelf. The onshore wells contain a sedimentary section ranging in age from Valanginian to Campanian, and attributable to the Bronze Whaler, Blue Whale-White Pointer, Tiger and Hammerhead supersequences. The succession reaches a maximum thickness of more than 357 m in the Madura 1 well. The section preserved in these wells records the evolution of depositional environments near the northern margin of the Bight Basin, from areally restricted non-marine deposition in the Early Cretaceous, through increasingly marine, although shallow and anoxic, conditions, to the local development of a small deltaic complex in the Late Cretaceous. Organic-rich non-marine shales of Early Cretaceous age, and Late Cretaceous organic-rich facies of marine affinity have been identified in wells in the study area., providing new information about the nature and extent of potential source rocks in the Bight Basin.

No abstract available

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

A prospectivity assessment of the offshore northern Perth Basin, Western Australia, was undertaken as part of the Australian Goverment's Offshore Energy Security Program.

The Early Cretaceous Gage Sandstone and South Perth Shale formations are a prospective reservoir-seal pair in the Vlaming Sub-basin. Plays include post-breakup pinch-outs in the Gage Sandstone with the South Perth Shale forming top seal. The Gage reservoir has porosities of 23-30% and permeabilities of 200-1,800 mD. It was deposited in palaeotopographic lows of the Valanginian breakup unconformity and is the lowstand component of the thick deltaic South Perth (SP) Supersequence. To characterise the reservoir-seal pair, a detailed sequence stratigraphic analysis was conducted by integrating 2D seismic interpretation, well log analysis and new biostratigraphic data. Palaeogeographic reconstructions for the SP Supersequence were derived from mapping higher-order prograding packages and establishing changes in sea level and sediment supply. Higher resolution Gage reservoir reconstructions were based on seismic facies mapping. The Gage reservoir forms part of a sand-rich submarine fan system and ranges from canyon confined inner fan deposits to middle fan deposits on a basin plain. Directions of sediment supply are complex, with major sediment contributions from a northern and southern canyon adjacent to the Badaminna Fault Zone. The characteristics of the SP Supersequence differ markedly between the northern and southern parts of the sub-basin due to variations in palaeotopography and sediment supply. Palaeogeographic reconstructions reveal a series of regressions and transgressions leading to infilling of the palaeo-depression. Palaeogeographic reconstructions for the SP Supersequence portray a complex early post-rift depositional history in the central Vlaming Sub-basin. The developed approach is applicable for detailed studies of other sedimentary basins.