Map of project area in southern Queensland and northern NSW

Map of project area in southern Queensland and northern NSW

The southern Thomson Orogen geology underlies the Channel Country in northwest New South Wales, and is one of the last major greenfield terranes in NSW. The Thomson Orogen has potential for arc- and ocean-crust-related gold and base metal deposits, while the area to the south of the orogen may have potential for Mississippi Valley-style zinc deposits. The prospective units are obscured by overlying Eromanga basin sediments, which present a significant impediment to exploration.

The Geological Survey of New South Wales (GSNSW) has made this terrane the focus of a series of projects since 2005. The primary objective is to lower mineral exploration risk by developing an effective means of exploring through the cover in the Thomson Orogen. This achievement can be measured by an increase in exploration investment in the area.

Surveys and interpretations completed by GSNSW from 2005-2013 involved seismic, gravity, geochemical and airborne geophysical data. Recent GSNSW regional mapping campaigns in the Koonenberry-Tibooburra and Cobar-Bourke regions have contributed detailed information from outcrops around the margins of the project area.

Starting in 2014, GSNSW participated in two major collaborative studies that:

  • helped define variations in the depth to basement and the nature of basement and cover sequences
  • advanced understanding of the structural framework, geological history and tectonic elements of the southern Thomson Orogen in NSW.

The projects included acquisition of new geophysical data and targeted geochronological, structural and mineral systems studies. The pre-competitive data, interpretations and reports will benefit a range of users to assess mineral potential; support mineral exploration and reduce the risks; guide land use planning; and support groundwater management.

Stratigraphic drilling

The recent stratigraphic drilling program including borehole completion reports

The collaborative studies

1. The Southern Thomson Orogen National Collaborative Framework (NCF) Project was a 3-year project between GSNSW, Geoscience Australia and the Geological Survey of Queensland to acquire and interpret multi-disciplinary geophysical, geochemical and geological data. This project started in 2014 and included geophysical acquisition programs (airborne electromagnetics, magnetotellurics, gravity), detailed analytical studies of stratigraphic units from core and surface samples, structural interpretation, and regolith and landscape studies. 

Results were released periodically via GSNSW and Geoscience Australia project webpages:

2. An ARC Linkage research program (2014–2018) was conducted with The University of Newcastle, the Geological Survey of Queensland, the University of Queensland, and the Queensland University of Technology. Coordinated geochronological, structural and geochemical studies at these universities targeted key geological questions. Multiple Honours, Masters and PhD theses about NSW geology have been completed (refer to the Southern Thomson ARC Linkage Project).. Outcomes have implications for understanding the geodynamic history and the mineral prospectivity of the southern Thomson Orogen and the greater Tasmanides. 

Click here for details of research projects associated with the ARC Linkage research program.

The results of many these student projects are included in the Australian Journal of Earth Sciences (AJES) Special Volume 65/7+8 , released in December 2018.

Both collaborative studies provided information about the style and timing of deformational events; the nature and hierarchy of faulting; implications for mineral prospectivity of the region; and the extent, lithology and geochronology of rock units. Comparisons were made with the Lachlan Orogen to the south, and the Delamerian Orogen to the west, to better understand the tectonic history of this portion of the Tasmanides.

Contact

Chris Folkes, Project Leader