Amino acid racemization (AAR) dating of the eolianite on Lord Howe Island is used to correlate several disparate successions and provides a geochronological framework that ranges from Holocene to Middle Pleistocene time. The reliability of the AAR data is assessed by analysing multiple samples from individual lithostratigraphic units, checking the stratigraphic order of the D/L ratios and the consistency of the relative extents of racemization for a suite of seven amino acids. Three aminozones are defined on the basis of the extent of racemization of amino acids in land snails (Placostylus bivaricosus) and 'whole-rock' eolianite samples. Aminozone A includes Placostylus from modern soil horizons (e.g. mean D/L-leucine ratio of 0.03±0.01) and whole-rock samples from unconsolidated lagoonal and beach deposits (0.10±0.01-0.07±0.03). Aminozone B includes Placostylus (0.45±0.03) and whole-rock samples from beach (0.48±0.01) and dune (0.45±0.02-0.30±0.02) units of the Neds Beach Formation, deposited during OIS 5. The oldest, Aminozone C, comprises Placostylus recovered from paleosols (0.76±0.02) and whole-rock eolianite samples (0.62±0.00) from the Searles Point Formation, which indicate the formation was likely deposited over several Oxygen Isotope Stages (OIS), during and prior to OIS 7. These data support independent lithostratigraphic interpretations and are in broad agreement with U/Th ages of speleothems from the Searles Point Formation and corals from the Neds Beach Formation, and with several TL ages of dune units in both formations. The AAR data reveal that eolianite deposition extends over a significantly longer time interval than previously appreciated and indicate that the deposition of the large dune units is linked to periods of relatively high sea level.

Exploration fundamentals related to predicted world economic growth and higher oil prices suggest a resurgence in exploration for oil and gas liquids in the Timor Sea in the next two years, despite a slow down in exploration drilling in the last 12 months.

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

This dataset contains polygons that bound parts of Irvine Hill forest. The polygons were constructed by drawing lines that join points which were pegged out as being boundaries of the Irvine Hill area. The main points were supplied by Whelans. The line joins and polygon making process was done by Geoscience Australia. The shapefile containing the data is: forestedge_irvineh.shp. Details of the fields can be seen below: Field Type Width Decimal---------------------------------------------------Shape FIELD_SHAPEPOLY 8 0Area FIELD_DECIMAL 12 3Perimeter FIELD_DECIMAL 12 3Plot3pef2_ FIELD_DECIMAL 11 0Plot3pef2_ FIELD_DECIMAL 11 0Entity FIELD_CHAR 14 0Layer FIELD_CHAR 32 0Elevation FIELD_DECIMAL 18 5Thickness FIELD_DECIMAL 18 5Color FIELD_DECIMAL 11 0Pointnumbe FIELD_DECIMAL 11 0Pointheigh FIELD_DECIMAL 18 5Pointcode FIELD_CHAR 8 0Sourcethm FIELD_CHAR 16 0Hectares FIELD_DECIMAL 16 3

A useful spin off of the soft photogrammetry is the opportunity to get one metre contours over the disturbed areas of the Island. For the north-east area of the Island 2km X 2km DEM contour tiles have been trialed in the CIGIS. Most are at a contour interval of 5 metres but tiles 2269 and 2469 have been done at a one metre contour interval. The DEM contours are surface contours. They pick up the reflective surface beneath the aircraft. The reflective surface may be the ground or it may be a dense vegetation canopy or rooftops etc. Further one metre contour coverage can be prepared on a cost recovered basis.

Product no longer exists, please refer to GeoCat #30413 for the data

Despite growing concerns about potential enhancement of global warming and slope failure by methane produced by gas hydrate dissociation, much uncertainty surrounds estimates of gas hydrate reservoir sizes, as well as methane fluxes and oxidation rates at the sea floor. For cold seep sediments of the eastern Mediterranean Sea, depth-dependent methane concentrations and rates of anaerobic oxidation of methane (AOM) are constrained by modeling the measured pore-water sulfate profile. The calculated dissolved methane distribution and flux are sensitive to the advective flow velocity, which is estimated from the depth distributions of conservative pore-water constituents (Na, B). Near-complete anaerobic oxidation of the upward methane flux is supported by the depth distributions of indicative biomarkers, and the carbon isotopic compositions of organic matter and dissolved inorganic carbon. Pore-water and solid-phase data are consistent with a narrow depth interval of AOM, 14-18 cm below the sediment-water interface. Based on an isotopic mass balance, the biomass of the microbial population carrying out oxidation of methane coupled to sulfate reduction at the given methane flux represents about 20% of the total organic carbon, which is a significant pool of in situ formed organic matter. Model results indicate that the asymptotic methane concentration is reached a few meters below the sediment surface. The predicted asymptotic concentration is close to the in situ saturation value with respect to gas hydrate, suggesting that the rate of shallow gas hydrate formation is controlled by the ascending methane flux. The proposed model approach can be used to predict the formation of gas hydrate, and to quantify methane fluxes plus transformation rates in surface sediments where fluid advection is an important transport mechanism.

The pmd*CRC A1 (Architecture) Project - A coherent concept aimed at predicting the mineral potential of major faults; Annual Review Meeting Perth, November 2003.

Tectonic evolution of the Tasman fold belt system in NE Queensland: Towards predictive mineral discovery. Annual Review Meeting Perth, November 2003 (I. Vos).