The Australian Geological Survey Organisation (AGSO) flew an airborne geophysical survey of 107,574 line kilometres covering parts of the onshore and offshore Gippsland Basin area in Victoria. AGSO flew the survey over two periods; November to December 1998 and January to April 1999. The survey formed part of the National Geoscience Mapping Accord. Flight lines were flown in an east-west direction with various line spacings and flying heights. The line spacing over the onshore component was 200 metres with a flying height of 80 metres above ground level. The offshore component was flown at 130 metres above sea level with line spacings of 400 and 800 metres. The latter spacing was used over the southeastern section of the survey area. The total magnetic intensity, gamma-ray spectrometric and digital elevation model data collected during the survey have been processed and are available for purchase. These data are sold as digital point located data, grids and hardcopy maps, by the Australian Geological Survey Organisation. A colour pixel image map depicting total magnetic intensity is also available.

This record represents a summary of the specifications of most surveys held in the National Airborne Geophysic Database (updated from 1998 when the third edition of this record was released).

This volume incorporates the Abstracts of papers presented at the BHEI annual meeting, May 2000.

During the TASGO Project in 1995, offshore deep seismic reflection profiles were recorded by AGSO?s R/V Rig Seismic along a series of traverses around Tasmania totalling 1758 km in length. Thirty-three portable AGSO seismic recording systems and six University of Tasmania Observatory fixed stations operated continuously onshore during this survey recording seismic arrivals from the ship?s air-guns. They provided wide-angle and refraction data with a range of source-receiver distances and azimuths. The arrivals have travel paths which pass through the major tectonic elements of Tasmania, and penetrate to below the crust-mantle boundary. They form a substantial new data set for imaging the detailed two-dimensional structure (when combined with the reflection profiles), and the regional three-dimensional structure of the State using tomographic techniques.This record documents the procedures used for processing and displaying the data and the structure of the archived data. The initial processing procedures were different for the analogue data and the digital data. The final processing, signal enhancement and display are common to both types of data.

Abstracts for Workshop organised jointly by the Australian Geological Survey Organisation, CSIRO Division of Exploration and Mining, and the Research School of Earth Sciences ANU. Workshop held on May 3rd and 4th at AGSO.

A digital elevation model (DEM) is a digital representation of the height of the terrain usually interpolated onto a regularly spaced grid. Traditionally, DEMs have been estimated from ground surveys, digitised topographic maps, satellite (SPOT) images and aerial photography. Since the advent of the Global Positioning System (GPS) for aircraft navigation, DEMs can be derived from positional and aircraft radar altimeter data recorded on airborne geophysical surveys. A DEM is useful in any situation where knowledge of the height, slope and aspect of the ground is important. DEMs are widely used in the following landscape studies - botanical, geochemical, environmental, forest, soil, geological, climatological, geophysical, glaciological and natural hazard (eg landslide). Florinsky (1988) gives a comprehensive list of applications for DEMs. These include: - stream flow modelling - landscape analysis - land use and soil mapping - geological/geophysical mapping - road design and other engineering projects Although DEMs have been derived from airborne geophysical survey data for several years, there is little information available on the precision and accuracy of these models. The purpose of this paper is to review the procedure for generating an airborne geophysical survey DEM and to investigate the sources and amplitudes of errors in these models.

Legacy product - no abstract available

A WET Labs SAFire multi-spectral and absorption meter was used to identify dissolved poly-aromatic hydrocarbons and anomalous biological activity in near surface waters. Over 6000 km of data were collected southwest of Noumea. No obvious hydrocarbon anomalies were detected but blue-green algal blooms (Trichodesmium ?), identified also by satellite and biological analysis (Dupouy et al, 2000), were commonly encountered in the survey area. An extremely high absorption anomaly centred at 162.7 deg E and 22.7 deg S, with a strong algal fluorescence signature at 440 nm excitation, is also likely to be from the same source.

This report describes gravity surveys conducted in Western Australia during 1991 and 1993, to establish new Absolute and Australian Fundamental gravity control stations in new areas and where existing fundamental gravity stations had been lost.

The geophysical data collected includes a total of 1827 km of multi-channel seismic data and 562 km of Chirper sonar data. A total of 11 gravity cores, 28 piston cores, 18 surface grabs and 11 short trigger cores were collected on the voyage. Water profile (CTD) measurements and water samples were collected at nine stations and seabed bottom photographs were made at 11 stations. The expedition discovered and mapped a shelf sediment drift deposit covering about 400 km2 lying in an >800m deep section of the George Vth basin west of the Mertz Glacier. It is a true "drift" deposit, since these sediments exhibit a depositional architecture indicative of contour-parallel sediment transport. A significant observation is that the drift thins to the north into an acoustically-transparent veneer; this observation implies that the drift is sourced from the outer continental shelf, with sediment being transported landwards, across the shelf and into an 850m deep inner shelf basin.