Geology and mineral deposits of The Granites-Tanami and Tennant Creek Inliers, Northern Territory

The Palaeoproterozoic Tennant Creek Inlier (TCI) and The Granites-Tanami Inlier (GTI) share similarities in their stratigraphy and tectonic evolution. Both are characterised by a sequence of flysch sediments and volcanics that accumulated in an intracratonic transtensional basin which was deformed (D1), metamorphosed and intruded by syn-orogenic I-type granitoids during the Barramundi Orogeny. Fluvial to shallow marine sediments, accompanied by felsic volcanism (plus mafics in the Davenport province) and penecontemporaneous subvolcanic intrusive activity, were deposited unconformably over the early rift sequence. Two episodes of mild deformation (D2 and D3) folded and faulted the sequence to produce basin and dome structures which were subsequently intruded by biotite-muscovite granites. Gold is the most important mineral commodity mined within both the inliers. It is concentrated in deposits which have a regional stratigraphic control (Mount Charles beds- GTI, Warramunga Formation ironstones- TCI) in combination with various structural controls at the local scale. The origin of the Au mineralising fluids is uncertain. Late felsic intrusives associated with the Barramundi Orogeny probably contributed magmatic fluid at the Au-Cu-Bi depositional stage at Tennant Creek, although a significant metamorphic fluid component is also evident. Vein quartz-hosted W, Au, Cu, Bi , U, Ag/Pb mineralisation in the Davenport province is within volcanics and sediments of the Ooradidgee Subgroup, and igneous intrusives (mainly gabbro/dolerite). The metal-bearing hydrothermal fluids are inferred to emanate from post-orogenic two-mica granites.

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Published (Metadata Record) 03/03/2026
Last updated 04/03/2026
Organisation Australian Federal Government
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