From Geoscience Australia
JSON format icon JSON RDF format icon RDF ISO19115-3 XML

Southern Thomson Magnetotelluric (MT) Survey Report and Preliminary Data Modelling

Created 17/10/2025

Updated 17/10/2025

JSON format icon JSON RDF format icon RDF ISO19115-3 XML

Geoscience Australia (GA) and the Geological Surveys of Queensland (GSQ) and NSW (GSNSW) are undertaking a multi-year, multi-disciplinary collaborative project with the aim of characterising the largely unexplored southern Thomson Oregon region (Figure 1). As part of this, a number of precompetitive geophysical datasets have been acquired or are planned to be acquired within the southern Thomson region. These datasets will support an improved understanding of the: - thickness and nature of cover; - geology obscured by recent sedimentary cover or regolith; and, - mineral systems potential of the region. Magnetotellurics is a passive geophysical technique which records the earth's natural time-varying electrical and magnetic fields to provide a measure of the subsurface conductivity/resistivity (these two physical properties are related as resistivity is the inverse of conductivity). The frequencies of magnetic and electrical sources recorded provide different depth information - audiomagnetotellurics (AMT) which records higher frequency data and images shallower electrical structure, while broadband MT (BBMT) records lower frequencies that image relatively deeper electrical structure. Although the depth of investigation of the technique varies according to the local resistivity structure, in general AMT images the shallowest upper crust only (14 km depth) and BBMT images the crust (~60 km depth). For the southern Thomson region, BBMT was acquired along 2 long and one shorter transect to provide pictures of the entire crust of the region, while AMT was acquired along shorter and higher-resolution lines to provide knowledge of the cover of the region. Within this document we detail the acquisition, processing and analysis of the MT data, and present preliminary resistivity models. These data, their analyses and models are released as underpinning datasets to support future geophysical analyses and geological interpretation. Accordingly, this report focuses primarily on the core geophysical aspects from acquisition through to preliminary modelling.

Files and APIs

Tags

Additional Info

Field Value
Title Southern Thomson Magnetotelluric (MT) Survey Report and Preliminary Data Modelling
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/02572a45-84bb-4ae0-9a91-e15645e96db5
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        143.8,
        -31.0
      ],
      [
        147.0,
        -31.0
      ],
      [
        147.0,
        -27.5
      ],
      [
        143.8,
        -27.5
      ],
      [
        143.8,
        -31.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Southern Thomson Magnetotelluric (MT) Survey Report and Preliminary Data Modelling". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/southern-thomson-magnetotelluric-mt-survey-report-and-preliminary-data-modelling