Geological framework of the Archean and Paleoproterozoic Tanami Region, Northern Territory
Issue Title: Special issue on the Tanami gold province, northern Australia The Tanami Region, a poorly exposed, mostly Paleoproterozoic province within the North Australian Craton, hosts a number of significant gold deposits in diverse settings. Rare exposures of 2,520-2,500 Ma amphibolite facies Ar...
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Veröffentlicht in: | Mineralium deposita 2007-01, Vol.42 (1-2), p.3-26 |
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Sprache: | eng |
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Zusammenfassung: | Issue Title: Special issue on the Tanami gold province, northern Australia The Tanami Region, a poorly exposed, mostly Paleoproterozoic province within the North Australian Craton, hosts a number of significant gold deposits in diverse settings. Rare exposures of 2,520-2,500 Ma amphibolite facies Archean gneiss and metasedimentary rocks form basement to the thick overlying metasedimentary succession of the 1,880-1,830 Ma Tanami Group. The basal unit of the Tanami Group is the Dead Bullock Formation, a fining-upward deep-water succession dominated by siltstone, carbonaceous siltstone, iron-rich siltstone and mafic sills. Carbonaceous- and iron-rich lithologies in the upper Dead Bullock Formation represent important hosts for gold mineralization. The conformably overlying Killi Killi Formation represents turbiditic sedimentary rocks that are correlated with the widespread Lander Rock beds of the Arunta Region. Sedimentation of the Tanami Group was terminated by regional deformation and greenschist to amphibolite facies metamorphism during the Tanami Event (D^sub 1^/M^sub 1^), at around 1,830 Ma. The Tanami Group is unconformably overlain by rhyolite, siliciclastic sedimentary rocks, and felsic ignimbrite of the Ware Group that were deposited at about 1,825-1,810 Ma. Subsequent ESE-WNW to SE-NW directed shortening (D^sub 2^), followed by NE-SW to E-W directed shortening (D^sub 3^), has resulted in open NE F^sub 2^- and NW F^sub 3^-trending folds in both the Tanami and Ware Groups. Voluminous granitoids, dominated by I-type, biotite granodiorite, and monzogranite were intruded in the interval 1,825-1,790 Ma and have been subdivided using geochemical criteria into the Birthday, Frederick, and Grimwade Suites. Basalt and immature sedimentary rocks of the Mount Charles Formation are restricted in extent to the Tanami mine corridor, and are interpreted to reflect a continental rift succession that was deposited around 1,800 Ma, with an early Archean sedimentary provenance. Steep S to SE dipping F^sub 4^-fold structures of Tanami and Ware Group metasedimentary rocks, many spatially associated with 1,825-1,790 Ma granitoid intrusions, indicate a period of SSE-directed regional shortening (D^sub 4^) syn-to-post the regional granitoid intrusive phase. A network of N to NW striking faults, several of which are interpreted as oblique thrusts with a component of left lateral movement, indicates a period of D^sub 5^ convergence during WSW-ENE to E-W directed shortening. T |
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ISSN: | 0026-4598 1432-1866 |
DOI: | 10.1007/s00126-006-0107-1 |