The preservation of marine black shales, especially during the Cretaceous, and their relationship to oceanic anoxic events (OAEs) has been extensively studies over the past three decades. However, molecular and isotopic geochemistry has revealed that there are many competing factors that lead to the presence of black shale in the fossil record. Each black shale `system? reflects the varying emphasis on the role of productivity vs preservation, autotrophy vs chemotrophy, and autochthonous (planktonic vs benthic vs bacterial) vs allochthonous (mainly terrestrial) inputs. It appears that each `system? represents a unique combination of the above processes. The Toolebuc Formations offers a natural laboratory where the relative contributions for individual processes can be addressed. Furthermore, the position of the anoxic/oxic boundary in relation to the sediment/water interface can be mapped with a high degree of confidence using a combination of organic and inorganic tracers. For example, increasing Ni/VO porphyrin and etio/DPEP ratios vary systematically with decreasing TOC contents as the boundary moves from within the water column to within the sediments, while Pr/Ph remains insensitive over the same transition. The importance of primary producers from the upper photic zone is best addressed using contents and carbon isotopes of metalloporphyrins, while sterane and isoprenoids are important markers for contributions from the lower photic zone. The role of the benthic community and recycled carbon is addressed using the carbon isotopes of individual compounds. When the anoxic/oxic and sediment/water interfaces coincide, specialised sulphur-oxidising bacteria flourish and represented by a diagnostic homologous series of mid-methylalkanes and even-number n-alkanes. Such a depositional model encompassing changing redox conditions is deemed to be a common thread in the deposition of many marine black shales and aspects of the Toolebuc `system? can be seen in the marine black shales of the Cenomanian-Turonian Greenhorn Formation, USA.

The technique of Reaction Gas Chromatography-Mass Spectrometry (R-GCMS) has been applied to the analysis of the polar extracts from a Heartbreak Ridge lignite (Bremer Basin, Western Australia; Eocene age) and a Monterey Formation shale (Naples Beach, USA; Miocene age). A catalyst, palladium black, is packed into glass liners for split vaporising injection. The liners are then placed into the injection port to catalyse the gas phase reaction of volatile polar mixtures. Hydrogen gas is used both as the reactant for hydrogenation/hydrogenolysis, and as the carrier gas for the subsequent separation. The reaction products are mostly hydrocarbons, and are swept on to the column where they are chromatographically resolved by the non-polar stationary phase. The products are then identified by mass spectrometry. The fully active catalyst is effective in hydrogenating and isomerising alkenes as well as partially hydrogenating aromatic moieties. Desulphurisation of thiols, sulphides, and thiophenes readily occurs also. Oxygenated compounds such as primary alcohols, acids, esters and ethers undergo a decarbonylation/decarboxylation, while secondary alcohols are reduced to the parent hydrocarbon. Polar fractions react to produce compound distributions that are characteristic of the organic matter source, namely angiosperm-derived triterpenoids and bacterially-derived hopanoids. The reaction of the polar fraction from the Monterey Formation shale results in the formation of high relative amounts of pristane and phytane. A suite of steroids and triterpenoids, typical of marine organic matter, is also observed. R-GCMS provides less detailed information on the exact nature of the functionalised lipids partitioned within the polar fraction compared to more conventional wet chemical analyses. However, this technique requires only a GCMS instrument fitted with a vaporising injector, which acts as a chemical reactor at the inlet of the column. The main advantages of R-GCMS are its speed, low sample requirement, and production of easily resolved and identified products.

As part of the Australian Government's National CO2 Infrastructure Plan (NCIP), Geoscience Australia undertook a CO2 storage assessment of the Vlaming Sub-basin. The Vlaming Sub-basin a Mesozoic depocentre within the offshore southern Perth Basin located about 30 km west of Perth, Western Australia. The main depocentres formed during the Middle Jurassic to Early Cretaceous extension. The post-rift succession comprises up to 1500 m of a complex fluvio-deltaic, shelfal and submarine fan system. Close proximity of the Vlaming Sub-basin to industrial sources of CO2 emissions in the Perth area drives the search for storage solutions. The Early Cretaceous Gage Sandstone was previously identified as a suitable reservoir for the long term geological storage of CO2 with the South Perth Shale acting as a regional seal. The Gage reservoir has porosities of 23-30% and permeabilities of 200-1800 mD. The study provides a more detailed characterisation of the post Valanginian Break-up reservoir - seal pair by conducting a sequence stratigraphic and palaeogeographic assessment of the SP Supersequence. It is based on an integrated sequence stratigraphic analysis of 19 wells and 10, 000 line kilometres of 2D reflection seismic data, and the assessment of new and revised biostratigraphic data, digital well logs and lithological interpretations of cuttings and core samples. Palaeogeographies were reconstructed by mapping higher-order prograding packages and establishing changes in sea level and sediment supply to portray the development of the delta system. The SP Supersequence incorporates two major deltaic systems operating from the north and south of the sub-basin which were deposited in a restricted marine environment. Prograding clinoforms are clearly imaged on regional 2D seismic lines. The deltaic succession incorporates submarine fan, pro-delta, delta-front to shelfal, deltaic shallow marine and fluvio-deltaic sediments. These were identified using seismic stratigraphic techniques and confirmed with well ties where available. The break of toe slope was particularly important in delineating the transition between silty slope sediments and fine-grained pro-delta shales which provide the seal for the Gage submarine fan complex. As the primary reservoir target, the Gage lowstand fan was investigated further by conducting seismic faces mapping to characterise seismic reflection continuity and amplitude variations. The suitability of this method was confirmed by obtaining comparable results based on the analysis of relative acoustic impedance of the seismic data. The Gage reservoir forms part of a sand-rich submarine fan system and was sub-divided into three units. It ranges from canyon confined inner fan deposits to middle fan deposits on a basin plain and slump deposits adjacent to the palaeotopographic highs. Directions of sediment supply are complex. Initially, the major sediment contributions are from a northern and southern canyon adjacent to the Badaminna Fault Zone. These coalesce in the inner middle fan and move westward onto the plain producing the outer middle fan. As time progresses sediment supply from the east becomes more significant. Although much of the submarine fan complex is not penetrated by wells, the inner fan is interpreted to contain stacked channelized high energy turbidity currents and debris flows that would provide the most suitable reservoir target due to good vertical and lateral sand connectivity. The middle outer fan deposits are predicted to contain finer-grained material hence would have poorer lateral and vertical communication.

Exploration targets in Palaeoproterozoic rocks (Willyama Supergroup) of the Outalpa Inlier, South Australia include the regionally extensive Bimba Formation, a marble and calc-silicate dominated unit known for its high base-metal content (Pb, Zn, Mn, Cu, Co). This unit is a correlative of the Ettlewood Calc-silicate in the Broken Hill Group (NSW) and is spatially associated with an important redox boundary that elsewhere in the Olary area served as the locus for several recently discovered mineral deposits (Kalkaroo, White Dam, Portia). This boundary is visible in aeromagnetic images of the Olary region and because of its obvious potential as both a marker horizon and guide to mineralisation, it was selected, along with the adjacent units, for detailed structural investigations as part of the Broken Hill Exploration Initiative. These investigations focussed on Ameroo Hill with the goal of better understanding the three dimensional geometry of the area as well as clarifying the origin of this important boundary and the extent to which it is structurally and/or stratigraphically controlled. Stratigraphy in the Ameroo Hill area incorporates one or more unconformities and has been deformed by at least four phases of pre-Adelaidean deformation (D1-D4). The Bimba formation immediately overlies one such unconformity and typically coincides with the transition of a variably oxidised succession of migmatised psammopelitic gneisses, quartz-albitites, calc-albitite, and minor calc-silicate rock (Curnamona Group) into an overlying sequence of psammopelitic schist that is increasingly graphitic towards its base (Strathearn Group) (Conor, 2000). Tight to isoclinal macroscopic folds identified in both sequences are of D2 and D3 age. They produced widespread structural repetition of lithological units and fold interference patterns that conform to the modified arrow-head type (non-coaxial deformation). D2 was also associated with northeast-directed thrust faulting that locally emplaced high-grade metamorphic rocks over lower-grade metamorphic facies. Microfabrics and metamorphic mineral assemblages in the Ameroo Hill area further indicate that D2 was accompanied by crustal thickening and deforms an even earlier high-grade layer-parallel fabric. The origin of this fabric remains unclear although formation in an extensional tectonic environment cannot be ruled out. A later episode of more upright W-E folding and associated shearing (D4) further complicates the regional structure, making for a complex outcrop pattern in which lateral and vertical continuity of the Bimba Formation is neither assured nor predictable without a thorough understanding of the three-dimensional structural geometry. Pb-Zn-Cu mineralisation in the Outalpa Inlier is not confined to a single horizon. The most obvious gossans in some areas are associated with a 5-20 m thick calc-silicate unit lying some tens of metres below the Bimba Formation and separated from it by a sequence of thin-bedded psammitic schist. This calc-silicate unit forms part of the underlying Curnamona Group (Ethiudna subgroup; Conor, 2000) and constitutes a secondary target for mineral exploration. It is manganiferous as well as sulphide rich, and is distinguished from the overlying Bimba Formation by its occurrence within a sequence of composite biotite gneisses (meta-sandstone) that are also host to a thin but regionally persistent quartzite layer. The most effective drilling programs and exploration strategies are likely to be those that target mineralisation at more than one stratigraphic level, including sub-Bimba depths, and which acknowledge that the original stratigraphy may have been substantially modified by deformation. Conor, C.H.H. (2000): Definition of major sedimentary and igneous units of the Olary Domain, Curnamona Province. Mesa Journal 19: 51-56.

Several novel series of branched alkanes have recently been detected in several Proterozoic (Officer Basin, Australia; Spitzbergen, Greenland) and Cretaceous (Eromanga Basin, Australia) sediments. Four C2n series and two C3n series were present in the very complex aliphatic fractions obtained from Neoproterozoic aged Munta sediments of the Officer Basin. The C2n series, also detected in the Spitzbergen sediments, are tentatively assigned as 5,5-diethylalkanes (e.g., Figure 1, Structure I), 6,6-diethylalkanes (II), 5-butyl,5-ethylakanes (III) and 6-butyl,6-ethylakanes (IV), with all showing strong odd or even carbon number preferences.

The North Pilbara Terrane has the largest variety of mineral deposits of any Archaean province. It contains the oldest known examples of volcanic-hosted massive sulphide (VHMS), lode Au, porphyry Cu, orthomagmatic Ni-Cu-PGE-V, pegmatitic Ta-Sn and epithermal deposits, with a diversity more characteristic of Phanerozoic mobile belts. Despite this diversity the North Pilbara Terrane appears to lack any major mineral deposits, with the exception of the Wodgina Ta-Sn pegmatite field. Below, we present the metallogenic history of the North Pilbara Terrane in the context of its tectonic development and then compare it to other Archaean provinces to assess controls on metal endowment.

The Australian Department of Defence and AGSO aimed to provide a calibration facility for three-component (vector) magnetometers and thereby a cost-effective service for defence and geoscientific purposes. Defence was the main provider of funding and would be spared the expensive and long-winded process of sending its instruments overseas for calibration. Australia would gain from having a world-class facility available to all magnetometer users. Three sets each of four coils are mounted orthogonally and connected to programmable current sources enabling the creation of magnetic fields between 0 ?T and 100 ?T in any direction. A sequence of field values is generated and compared with the corresponding outputs of the magnetometer under test. The system computer then automatically prints the main parameters describing the instrument?s sensor angles, sensitivities, linearities, and test conditions. Background field variations over the measurement period are subtracted. Our system is capable of generating fields to a magnitude accuracy of 20 ppm and a directional precision of about 10 seconds of arc assured by checking the generated fields with a standard scalar (proton) magnetometer. The Defence Department?s needs and its policy of encouraging general use have enabled AGSO, in close collaboration with its suppliers, to create a unique facility for terrestrial and space exploration, for general scientific research, and a foundation for future client needs. Already AGSO is developing, with funds from the CRC for Satellite Systems, the capacity to magnetically characterise FedSat which will carry a three-component fluxgate magnetometer into polar orbit early next year. FedSat is an Australian Government Centenary of Federation project.

No abstract available

The Western Tharsis deposit, located in the Cambrian Mount Read Volcanic Belt of western Tasmania, is one of 22 mainly Cu-Au deposits in the Mount Lyell district. Although Western Tharsis is characterized mainly by disseminated pyrite-chalcopyrite like most other deposits in the Mount Lyell district, it also contains bornite-rich ores characteristic of a second, less common type of deposit in the Mount Lyell district. The deposit is stratabound and occurs within intermediate and felsic volcanic rocks belonging to the Central Volcanic Complex. Alteration is developed symmetrically around the ore zone, with an ore-bearing core characterized by a quartz-chlorite?sericite assemblage. The core is enveloped by a pyritic quartz-pyrophyllite?topaz?fluorite?zunyite?woodhouseite "advanced argillic" assemblage with local bornite-bearing ore zones. This zone, in turn, is enveloped by a pyritic quartz-sericite assemblage and then by an outermost quartz-chlorite-carbonate-sericite?albite assemblage that lacks pyrite. The bornite-related pyrophyllite-bearing assemblage is more characteristic of ?high sulfidation? epithermal rather than VHMS-related alteration assemblages. The close relationship of this assemblage to the quartz-chlorite?sericite assemblage associated with disseminated pyrite-chalcopyrite suggests that the bornite and chalcopyrite assemblages formed as two stages of one mineralizing event. The chalcopyrite-pyrite ore zone is characterised by extreme enrichment (relative to regional background) in As, Bi, Ce, Cu, Mo, Ni, S and Se. With the exception of Mo, these elements are also enriched, but at a much lower level, in the pyrite-bearing advanced argillic and sericitic halos. Positive Eu anomalies and pronounced depletion in K, Cs, Mg, Be, Ga, Rb, Y, MREE and HREE are associated with the advanced argillic assemblages. The outermost carbonate-bearing halo is highly enriched in C, Ca and Mn, and weakly enriched in Zn and Tl. The dispersion patterns and alteration assemblages observed at Western Tharsis are quite unlike those of Zn-Pb-rich volcanic-hosted massive sulfide (VHMS) deposits in western Tasmania. Rather, the dispersion patterns observed at Western Tharsis are more akin to those surrounding porphyry Cu deposits and related acid-sulfate Cu-Au deposits. Geological relationships and radiogenic isotope data may suggest an Ordovician timing for Mt Lyell Cu-Au mineral deposits.

The paper reveiws metallogenic evolution of Australia. A comparison between Archaean, Proterozoic and Phanerozoic metallogeny reveals that in general there exist more similarities between the Archaean and the Phanerozoic that those between the Archaean and the Proterozoic and between the Proterozoic and the Phanerozoic metallogeny. The paper argues that the contribution of plate tectonic processes in the geological evoultion and metallogeny of Australian Proterozoic need revaluation for assessing mineral potetnial of deposit styles which are traditionally considered to be not important but large deposits of each are known to exist in the Proterozoic elsewhere.