This study tested and assessed several methods for identifying and describing physical and chemical characteristics of nearshore sediments in East Antarctica. The study emphasised non-destructive techniques that can be used with small volumes of sample. There were three key aims: 1. Provide information about analytical techniques that are non-destructive and can be used on small-volume samples, 2. Apply these techniques to a set of samples where sufficient material is available and compare the results with the outcomes of traditional geochemical techniques, and, 3. Gain additional information on sedimentary processes in the nearshore environment in East Antarctica. Sediment samples from the Antarctic region are especially difficult to collect because of large logistical requirements and are thus highly valuable. Sediment traps are an example of samples with typically small volumes. Such samples provide valuable information about the nature and quantity of marine sediment in the water column and are highly sought after by researchers. By testing characterisation methods on larger samples, this scoping study provides recommendations for analysing small-volume samples, using non-destructive techniques and techniques that can provide additional information to traditional analysis. In this study, laser Raman spectroscopy and infrared spectroscopy were used to provide qualitative mineralogy for calcite, aragonite, and biogenic silica. Microtextural analysis of quartz grains was undertaken with a scanning electron microscope to provide information on the physical transport processes that the sediment has undergone. With this technique we were also able to identify chemical weathering features. Raman spectroscopy is a relatively rapid technique and has simple sample preparation requirements. The technique can target individual grains but can also measure bulk mineralogy. It is a promising technique for distinguishing mineral polymorphs but scope for quantification is limited for multi-component mixtures compared to traditional mineralogical methods like x-ray diffraction (XRD). Infrared spectroscopy is also quick and sample preparation is minimal. The technique requires more sample than will probably be recovered from sediment traps or sediment cores, at least 15 grams. For samples with large proportions of terrigenous sediment, distinguishing biogenic minerals is difficult because of low concentrations. Acquisition of more reference spectra for minerals of interest in marine substrates (particularly biogenic minerals) would be useful for comparing with sample spectra. Microtextural analysis provides detailed information about potential transport processes but sample preparation and analysis is time-consuming when compared to geochemical analysis. The technique is also somewhat destructive as quartz grains need to be cleaned and mounted. We recommend that an absolute minimum of 20 quartz grains is required for microtextural analysis. Microtextural analysis of sediments from near Davis Station suggests reworking of sediments in a subaqueous environment and minimal aeolian transport. There is also evidence of secondary silica precipitation and minor dissolution of quartz grains.

No abstract available

Harold Raggatt Award for Distinguished Lecturer Series: "Offshore Australian oil families and petroleum systems" by Dr Dianne Edwards presented as a powerepoint presentation on 1 August 2001.

Web-based CDROM providing links to national and state surveys' Internet pages relevant to mineral exploration in Australia.

The borehole temperature data collection contains Logs recorded by Geoscience Australia from a ranges of wells and boreholes throughout Australia.

This disc contains scanned PDF copies of geophysical and geological logs held by Geoscience Australia from the archives of the former Australian Atomic Energy Commission. These logs date from the around 1973 to 1975, and are specific to Honeymoon and Gould's Dam deposits. Two other discs with PDF scans of exploration in South Australia also exist and may be of interest.

<p>Iron oxide-copper-gold (IOCG) mineral systems are a desirable undercover exploration target due to their large alteration footprint and potentially high metal content. To assist in understanding the potential for IOCG mineral systems beneath cover in the Tennant Creek to Mount Isa region as part of Exploring for the Future, a predictive mineral potential assessment has been undertaken using a knowledge-based, mineral systems approach.<p>This mineral potential assessment uses a 2D, GIS-based workflow to qualitatively map four key mineral system components: (1) Sources of metals, fluids and ligands, (2) Energy to drive fluid flow, (3) Fluid flow pathways and architecture, and (4) Deposition mechanisms, such as redox or chemical gradients. For each of these key mineral system components theoretical criteria, representing important ore-forming processes, were identified and translated into mappable proxies using a wide range of input datasets. Each of these criteria are weighted and combined using an established workflow to produce the final map of IOCG potential, all of which is well documented in the accompanying IOCG Assessment Criteria Table.<p>Two assessments have been undertaken. The first is a comprehensive assessment containing all available geospatial information and is highly reliant on the level of geological knowledge. As such, it preferentially highlights mineral potential in well-understood areas, such as outcropping regions and performs less well in covered areas, where there is a greater likelihood of data gaps. The second assessment utilises only datasets which can be mapped consistently across the assessment area. As such, these are predominately based on geophysical data and are more consistent in assessing exposed and covered areas. However, far fewer criteria are included in this assessment.<p>Both assessment highlight new areas of interest in underexplored regions, of particular interest a SW-NE corridor to the East of Tennant Creek of moderate/high potential in the Barkly region. This corridor extends to an area of moderate potential in the Murphy Inlier region near the Gulf of Carpentaria on the NT/QLD border.

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.

No abstract available

A user interactive guide to Geoscience Australia's Antarctic information sources and related online content