The formation of passive margins has been intensively studied on the Iberian-Newfoundland margins for over two decades leading to complex models for the formation of conjugate nonvolcanic rifted margins. The main area of debate is focussed on deciphering the nature of the so-called transitional zone between unambiguous continental and oceanic crust. The transitional zone often displays characteristics of both continental and oceanic crust. The Great Australian Bight and Wilkes Land margins are type-examples of conjugate nonrifted volcanic margins, but much less well studied than the Iberian-Newfoundland margins. Research along the Southeast Indian Ocean margins has been propelled by Australia's submission to the United Nations Convention of the Law of the Sea, yet the study of the margins has been limited to research on particular regions on either the Australian or Antarctic margins. No consistent stratigraphy has been derived that would allow a unified study of this margin pair. This thesis uses seismic and potential field data to provide a consistent interpretation across the two margins in terms of sedimentary sequences and crustal structure for the first time. The interpretation of both margins provides insight into the nature and formation of the transitional zone. A new sequence stratigraphy for the Wilkes Land margin has been developed to correlate with the interpretation of Totterdell et al. (2000) along the Great Australian Bight margin. Combined with the crustal structure classification of Leitchenkov et al. (2007) a revised model for the breakup and formation of the transitional zone was developed. The formation of the transitional zone is interpreted to be the result of extension of the two plates and the successive breakup of continental crust and mantle followed by the emplacement of oceanic mantle, initially without the formation of oceanic crust. The presence of the Moho within the seismic data shows that the transitional zone is underlain by mantle rocks. Continental mantle is interpreted to be exhumed to form prominent basement highs on both margins. Seaward of these highs, the change in basement architecture and the presence of magnetic anomaly 34 (83Ma) is interpreted to correlate with the juxtaposition of continental mantle and the emplacement of oceanic mantle. This is consistent with well subsidence data from Totterdell et al. (2000) which shows a change in the rate of subsidence at this time. The location of the Transitional Zone-Ocean Boundary (TZOB) and Transitional Zone- Continent Boundary (TZCB) are repositioned as a result of this study. The TZOB is located further landward of previous interpretations by Sayers et al. (2001) and Colwell et al. (2005). The interpretation of the transitional zone being underlain by mantle rocks renders the term Continent-Ocean Boundary (COB) invalid as, continental crust is not found immediately next to oceanic crust.

3D visualisation of the Mount Isa Crustal Seismic Survey

Deposition: Multi-fluid systems, depositional processes and targeting

Camp- to deposit-scale zonation of hydrothermal alteration in the St Ives gold camp, Yilgarn Craton, Western Australia: evidence for two fluid systems?

A schematic diagram showing Australia's Continental Shelf Jurisdictional areas around Australia.

This workshop presented the results of the Mount Isa deep crustal seismic survey to mineral explorers and other interested geoscientists. The survey was carried out in 2006 across the Mount Isa Inlier and the Lawn Hill Platform in northwest Queensland as a collaborative project between Geoscience Australia, the Queensland Government (Geological Survey of Queensland), Zinifex Pty Ltd and the Predictive Mineral Discovery Cooperative Research Centre (pmd*CRC) using the facilities of ANSIR (the National Research Facility for Earth Sounding).

This article describes the geology of Northeastern Eyre Peninsula in South Australia, and calls particular attention to the geological significance of a very prominent magnetic intensity contrast that is interpreted to represent the northern extension of the Kalinjala Mylonite Zone.

Map produced for the Office of the Australian Building and Construction Commissioner showing the oil and gas fields, production locations and hydrocarbon pipelines on a background of the AMB data. Produced for the internal use by this Office.

All available processed seismic data and well completion reports relevant to the 2009 Acreage Release. Datasets available in Geoframe, Kingdom and Landmark workstation formats.

Widespread seagrass dieback in central Torres Strait, Australia has been anecdotally linked to the delivery of vast quantities of terrigenous sediments from New Guinea. The composition and distribution, and sedimentological and geochemical properties, of seabed and suspended sediments in north and central Torres Strait have been determined to investigate this issue. In northern Torres Strait, next to Saibai Island, seabed sediments comprise poorly sorted, muddy, mixed calcareous-siliciclastic sand. Seabed sediments in this region are dominated by aluminosilicate (terrigenous) phases. In central Torres Strait, next to Turnagain Island, seabed and suspended sediments comprise moderately sorted coarse to medium carbonate sand. Seabed sediments in this region are dominated by carbonate and magnesium (marine) phases. Mean Cu/Al ratios for seabed sediments next to Saibai Island are 0.01, and are similar to those found in New Guinea south coastal sediments by previous workers. Mean Cu/Al ratios for seabed sediments next to Turnagain Island are 0.02, indicating an enrichment of Cu in central Torres Strait. This enrichment comes from an exogenous biogenic source, principally from foraminifers and molluscs. We could not uniquely trace terrigenous sediments from New Guinea to Turnagain Island in central Torres Strait. If sediments are a factor in the widespread seagrass dieback in central Torres Strait, then our data suggest these are marine-derived sediments sourced from resuspension and advection from the immediate shelf areas and not terrigenous sediments dispersed from New Guinea rivers. This finding is consistent with outputs from recently developed regional hydrodynamic and sediment transport models.