<sup>40</sup>Ar‐<sup>39</sup>Ar and K‐Ar age constraints on the Early Proterozoic Tennant Creek Block, northern Australia, and the age of its gold deposits∗

Compston, D.M.; McDougall, Ian

doi:10.1080/08120099408728171

Cited by 21 publications

(11 citation statements)

References 11 publications

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“…Another type of deposit which appears to require oxidized £uids for either metal transport or deposition is iron oxide-hosted Cu^Au deposits, including the giant Olympic Dam deposit in South Australia. The oldest, and one of the better studied districts^Tennant Creek in the Northern Territory, Australia^has been dated at about 1.83 Ga [61]. Again the emergence of this class of deposit appears to be linked to the development of an oxygenated atmosphere and hydrosphere.…”

Section: Implications Of Hydrosphere Evolution To Mineralizationmentioning

confidence: 99%

Barite, BIFs and bugs: evidence for the evolution of the Earth’s early hydrosphere

Huston

Logan

2004

Earth and Planetary Science Letters

282

142

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The presence of relatively abundant bedded sulfate deposits before 3.2 Ga and after 1.8 Ga, the peak in iron formation abundance between 3.2 and 1.8 Ga, and the aqueous geochemistry of sulfur and iron together suggest that the redox state and the abundances of sulfur and iron in the hydrosphere varied widely during the Archean and Proterozoic. We propose a layered hydrosphere prior to 3.2 Ga in which sulfate produced by atmospheric photolytic reactions was enriched in an upper layer, whereas the underlying layer was reduced and sulfur-poor. Between 3.2 and 2.4 Ga, sulfate reduction removed sulfate from the upper layer, producing broadly uniform, reduced, sulfur-poor and iron-rich oceans. As a result of increasing atmospheric oxygenation around 2.4 Ga, the flux of sulfate into the hydrosphere by oxidative weathering was greatly enhanced, producing layered oceans, with sulfate-enriched, ironpoor surface waters and reduced, sulfur-poor and iron-rich bottom waters. The rate at which this process proceeded varied between basins depending on the size and local environment of the basin. By 1.8 Ga, the hydrosphere was relatively sulfate-rich and iron-poor throughout. Variations in sulfur and iron abundances suggest that the redox state of the oceans was buffered by iron before 2.4 Ga and by sulfur after 1.8 Ga. Crown

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Section: Implications Of Hydrosphere Evolution To Mineralizationmentioning

confidence: 99%

Barite, BIFs and bugs: evidence for the evolution of the Earth’s early hydrosphere

Huston

Logan

2004

Earth and Planetary Science Letters

282

142

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“…Five mines had intial reserves of 2 Mt to 5 Mt and a number of smaller, high-grade deposits have also been exploited though reserves are now mostly worked-out (Huston et al, 1993;Davidson and Large, 1994). Compston and McDougall (1994) established that ironstone formation and mineralization occurred over a short time interval and have a minimum age of 1830 Ma to 1825 Ma. Coupled with structural constraints, this establishes a close temporal link with the ca.…”

Section: Tennant Creek Depositsmentioning

confidence: 99%

Australian Proterozoic Iron Oxide-Cu-Au Deposits: An Overview with New Metallogenic and Exploration Data from the Cloncurry District, Northwest Queensland

Williams

Pollard

2001

Exploration and Mining Geology

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Enigmatic hydrothermal vein/breccia/replacement Cu-Au deposits with magnetite and/or hematite are well-represented in Australian 1850 Ma to 1500 Ma terrains and associated with different-aged synorogenic intrusions in the Tennant Creek Block (ca. 1850 Ma); the Gawler-Curnamona region (1640 Ma to 1590 Ma); and the Cloncurry district (Mount Isa Eastern Fold Belt, 1540 Ma to 1500 Ma with a possible earlier event at ca. 1600 Ma). No deposits are known to be coeval with various 1780 Ma to 1610 Ma anorogenic intrusions. Deposits are hosted by many different rock-types with varying metamorphic grade including granites and various supracrustal rocks. Depth of mineralization varied from many kilometers in semiductile crust (e.g., Cloncurry deposits) to very shallow (e.g., Olympic Dam). Ore deposition near Cloncurry occurred in brittle-ductile shear zones from geochemically variable and complex, CO2-rich, 300°C to 500°C, high salinity fluids with magmatic stable isotopic signatures. Recently published studies of a giant granitoid-hosted magnetite vein complex at the Lightning Creek prospect (>1000 Mt magnetite) suggest it is a product of internal differentiation and endogenous Fe and Cu-rich hydrous-carbonic fluid phase generation within a quartz monzodiorite-monzogranite intrusion. Coupled with other field relationships, this points to a possible genetic relationship with intermediate (55 to 65 wt% SiO2) members of an alkaline and partly shoshonitic granitoid supersuite which appears to have both mantle and crustal source components from εNd evidence. In constrast, main-phase mineralization at Olympic Dam in the Gawler Craton is distinguished by hematite-phyllosilicate alteration and chalcopyrite-bornite-chalcocite zoning, reflecting fluid mixing in a high level (<250°C) system with a probable large component of meteoric water. Early high-temperature parageneses and fluid inclusions imply that the extensive hematitic breccias overprinted an older magnetite system which may have had similarities with those at Lightning Creek and Ernest Henry in the Cloncurry district.Deposits of this family are inherently difficult to find and evaluate as even within a single district, there is no reliable relationship between the location of ore and any specific combination of geophysical characteristics. Diverse alteration assemblages, geochemistry and physical characteristics suggest the deposits reflect the interaction of multi-sourced fluids with different host rocks in a wide range of geological environments. Recent discoveries and research in the Cloncurry district have extended the range of deposit models available and aid the development of a rudimentary classification in which economic and exploration characteristics can be linked to variations in the mechanisms and environments of ore formation.

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“…The Warramunga Formation was deposited at ~1865-1860 Ma (Fig. S3; Compston, 1995;Smith, 2001;Donnellan, 2013;Maidment et al, 2013). Disseminated magnetite is relatively abundant (up to several volume percent) in lower parts of the sequence, whereas the hematitic shales and most ironstones appear to be most common in upper parts of the Warramunga Formation.…”

Section: Tennant Creek Goldfield Australia -Paleoproterozoic Au-cu-bi-fe Depositsmentioning

confidence: 99%

Iron oxide copper-gold (IOCG) deposits – A review (part 1): Settings, mineralogy, ore geochemistry and classification

Skirrow¹

2022

Preprint

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Characteristics of ten of the world's metallogenic provinces hosting iron oxide Cu-Au (IOCG) deposits have been critically assessed, including geochronology, geological and tectonothermal evolution, alteration-mineralisation parageneses, and ore geochemistry. A new classification framework is proposed in which IOCG deposits form the major part of a global family of Cu-Au-Fe (± Co, REE) or CGI deposits that also includes Fe-rich Cu-Au deposits lacking significant iron oxides. The CGI family is subdivided on the basis of combined tectonic setting, ore geochemistry, and oxidation state of ore-related mineralogy. Three subtypes of CGI deposits have elevated REE ± U, F and Ba and/or enrichments in Co (± Ni, Bi, Se, Te), with known deposits occurring in Precambrian syn-and post-orogenic settings. A fourth subtype of CGI deposits generally lacks significant enrichments in REE, U, F, Ba, Co, Ni, Bi, Se and Te and occur mainly in Phanerozoic Andean type magmatic arc settings. The REE-and/or Co-rich CGI deposit subtypes are geologically and geochemically distinct from porphyry Cu (-Au), skarn Fe-Cu and iron oxideapatite (IOA) deposits, although there are some shared features. The low-REE-U-Co arc-hosted

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⁴⁰Ar‐³⁹Ar and K‐Ar age constraints on the Early Proterozoic Tennant Creek Block, northern Australia, and the age of its gold deposits∗

Cited by 21 publications

References 11 publications

Barite, BIFs and bugs: evidence for the evolution of the Earth’s early hydrosphere

Barite, BIFs and bugs: evidence for the evolution of the Earth’s early hydrosphere

Australian Proterozoic Iron Oxide-Cu-Au Deposits: An Overview with New Metallogenic and Exploration Data from the Cloncurry District, Northwest Queensland

Iron oxide copper-gold (IOCG) deposits – A review (part 1): Settings, mineralogy, ore geochemistry and classification

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40Ar‐39Ar and K‐Ar age constraints on the Early Proterozoic Tennant Creek Block, northern Australia, and the age of its gold deposits∗

Cited by 21 publications

References 11 publications

Barite, BIFs and bugs: evidence for the evolution of the Earth’s early hydrosphere

Barite, BIFs and bugs: evidence for the evolution of the Earth’s early hydrosphere

Australian Proterozoic Iron Oxide-Cu-Au Deposits: An Overview with New Metallogenic and Exploration Data from the Cloncurry District, Northwest Queensland

Iron oxide copper-gold (IOCG) deposits – A review (part 1): Settings, mineralogy, ore geochemistry and classification

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Product

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⁴⁰Ar‐³⁹Ar and K‐Ar age constraints on the Early Proterozoic Tennant Creek Block, northern Australia, and the age of its gold deposits∗