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Warrumbungle Volcano: Facies architecture and evolution of a complex shield volcano

Created 17/10/2025

Updated 17/10/2025

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We present a new geological map of Warrumbungle Volcano created from volcanic facies field mapping, new geophysical, geochemical, and geochronological data as well as data from previous studies. Field mapping and petrography defined 19 volcanic and 2 mixed volcanic-sedimentary facies. Facies identification and distribution in conjunction with geochemical analyses indicate an early shield-forming phase of predominantly mafic and intermediate lavas and pyroclastic deposits, and minor felsic lavas deposited on an irregularly eroded basement of Surat and Gunnedah basin rocks. The shield was subsequently intruded by felsic intermediate to felsic magmas that formed dykes and other intrusions including possible cryptodomes, and also erupted as lava domes and block-and-ash-flow deposits. A radial dyke swarm cross-cuts most units, although is concentrated within basement sandstone surrounding the central area of the volcano, suggesting late inflation accompanied by dyke emplacement. Geochemistry indicates differentiation of a single although repeatedly recharged alkaline magmatic suite. Fractionation of olivine, Ti-magnetite and clinopyroxene occurred in mafic magmas, and after reaching 62 wt% SiO2 crystallisation of apatite and alkali feldspar took place. A new U-Pb zircon SHRIMP magmatic crystallisation age of 16.25 +/- 0.12 Ma on a felsic block-and-ash flow deposit is in agreement with the recalculated 40Ar/39Ar isochron dates of previous workers. Based on our mapping and the use of volcanic facies to define mappable units, we recommend the previous Warrumbungle Volcanics be elevated from formation to group status and renamed the Warrumbungle Volcanic Complex.

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Field Value
Title Warrumbungle Volcano: Facies architecture and evolution of a complex shield volcano
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/d4929169-c8f1-4e79-ade9-8719c1d8b7a2
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 01/01/2014 - 05/07/2020
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        148.8,
        -31.5
      ],
      [
        149.2,
        -31.5
      ],
      [
        149.2,
        -31.1
      ],
      [
        148.8,
        -31.1
      ],
      [
        148.8,
        -31.5
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Warrumbungle Volcano: Facies architecture and evolution of a complex shield volcano". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/warrumbungle-volcano-facies-architecture-and-evolution-of-a-complex-shield-volcano