This survey was acquired across the northern Yilgarn Craton in May and June 2010. It builds on the existing network of deep-crustal seismic surveys, and was aimed at improving the understanding of the crustal structure of Western Australia. The survey was designed to extend across the Yilgarn Craton from the Archean Narryer Terrane through major bounding and internal structures of the Youanmi Terrane into the Kalgoorlie Terrane of the Eastern Goldfields Superterrane.
The survey was funded through the department’s Exploration Incentive Scheme (EIS). Acquisition, processing and interpretation were managed by Geoscience Australia (GA). Terrex Seismic Pty Ltd, an Australian company based in Perth, carried out the seismic data acquisition. Dynamic Satellite Surveys Pty Ltd undertook transect line survey pegging along a predefined route prior to the data acquisition phase.
Three individual seismic lines (10GA-YU1, 10GA-YU2 and 10GA-YU3), along with complementary MT data, were acquired along the Youanmi survey. The lines cross the northern part of the Yilgarn Craton from the Narryer Terrane in the northwest, across major bounding and internal structures of the Youanmi Terrane and into the Kalgoorlie Terrane of the Eastern Goldfields Superterrane. The northwestern end of YU1 is east of the southern end of line CP3 from the 2010 Capricorn seismic survey. The two surveys are linked by the Southern Carnarvon Basin seismic survey, acquired by GA in 2011. The eastern end of YU2 crosses major structures on the western side of the Eastern Goldfields Superterrane, which were also imaged by the 2001 GA seismic line (01AGS-NY1), about 120 km to the southeast.
The main objectives for the Youanmi traverses were to:
- image deep structure in the Narryer Terrane, the oldest component of the Yilgarn Craton, and the region that contains the oldest known crust in Australia
- image the contact between the Narryer Terrane and the adjacent, highly mineralised Murchison Domain of the Youanmi Terrane
- investigate the nature of granite–greenstone contacts and the overall shape, depth, and structure of greenstone belts
- compare the nature, orientation, and crustal penetration of mineralised and unmineralised structures
- develop a three-dimensional (3D) image of the mafic–ultramafic Windimurra Igneous Complex
- image the Ida Fault, the boundary, between the Youanmi Terrane and the Kalgoorlie Terrane in the Eastern Goldfields Superterrane, and compare the deep structure in these adjacent terranes
- link with previously acquired deep-crustal seismic traverses in the Eastern Goldfields Superterrane.
The migrated uninterpreted and interpreted seismic data and images for lines 10GA-YU1, 10GA-YU2 and 10GA-YU3. are available for download (in multiple formats) directly from Geoscience Australia. All MT data are available for download from the Airborne Geophysics Index (MAGIX) layers using GSWA’s interactive map-viewing application GeoVIEW.WA.
Preliminary interpretations of the Youanmi deep crustal seismic lines (10GA-YU11, 10GA-YU2, and 10GA-YU3) were released at a public workshop held at the department’s Perth headquarters on 27 February 2013. The workshop consisted of 12 presentations and was accompanied by the release of a series of extended abstracts and geological plates. All of the data, including the 12 PowerPoint presentations, can be downloaded from the links below.
Youanmi/Southern Carnarvon workshop (27 February 2013) — presentations
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