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Granitoids of northeastern Tasmania

Created 17/10/2025

Updated 17/10/2025

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The granitoids of northeastern Tasmania comprise the composite Scottsdale, Blue Tier, and Eddystone batholiths, and intrude the folded Ordovician to Lower Devonian Mathinna beds, which consist of interbedded quartzwacke, siltstone, and slate, regionally metamorphosed to low grade. The granitoids were intruded in the Devonian, having K-Ar ages ranging between 395 and 368 Ma. They post-date the regional folding of the country rocks, which is correlated with the Tabberabberan deformation of eastern Australia. Emplacement was at a high level, with narrow metamorphic aureoles, and the granitoids are associated with a small amount of volcanics. The granitoids fall into four types: granodiorite, biotite adamellite, biotite-garnet adamellite, and alkali-feldspar granite. The last type is strongly metasomatised and associated with tin mineralisation. Field relations indicate that, generally, the granodiorite plutons are the oldest and the alkali-feldspar granite plutons the youngest. The granitoids have been derived from partial melting of both igneous and sedimentary source rocks. Unequivocal S-type granites are reStricted to the Eddystone batholith. Minor crystal fractionation or restite unmixing occurred within plutons. The alkali-feldspar granites were derived from adamellite magma by crystal fractionation.

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Field Value
Title Granitoids of northeastern Tasmania
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/bfbff3cb-8c69-4cee-9185-dda57cfeec0c
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        147.08,
        -41.78
      ],
      [
        148.4,
        -41.78
      ],
      [
        148.4,
        -40.78
      ],
      [
        147.08,
        -40.78
      ],
      [
        147.08,
        -41.78
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Granitoids of northeastern Tasmania". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/granitoids-of-northeastern-tasmania