Granite-hosted gold mineralization at Timbarra, northern New South Wales, Australia

Mustard, R.

doi:10.1007/s001260100188

Cited by 45 publications

(30 citation statements)

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“…The Au deposit at Timbarra in the New England Fold Belt, East Australia, is an example of an intrusion-related gold deposit with disseminated gold mineralization and minor late-stage vein mineralization in the roof zone of a composite pluton (Mustard, 2001(Mustard, , 2004. The Timbarra pluton consists of two major intrusions (Bungulla monzogranite and Stanthorpe syenogranite) that have several texturally and chemically different zones (for details see Mustard, 2001Mustard, , 2004; see Data Repository 1 ).…”

Section: Geology Of the Timbarra Pluton And Sample Descriptionmentioning

confidence: 99%

“…The Timbarra pluton consists of two major intrusions (Bungulla monzogranite and Stanthorpe syenogranite) that have several texturally and chemically different zones (for details see Mustard, 2001Mustard, , 2004; see Data Repository 1 ). Seven individual zones of the pluton can be readily distinguished based on texture, grain size, mineralogy, and field relationships.…”

Section: Geology Of the Timbarra Pluton And Sample Descriptionmentioning

confidence: 99%

“…Ulrich-Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia. deposits (i.e., Fort Knox and Timbarra; Bakke, 1995;Mustard, 2001Mustard, , 2004Thompson et al, 1999; Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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Gold and metal enrichment in natural granitic melts during fractional crystallization

Mustard

Ulrich

Kamenetsky

et al. 2006

Geol

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102

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Metal evolution in a composite granitic pluton was tracked by analyzing melt inclusions in 11 quartz samples from 7 zones at the Timbarra gold deposit, Australia. We present the first quantitative microanalyses of gold (Au) in granitic silicate melt inclusions using laser ablation inductively coupled plasma mass-spectrometry and show how Au and other metals become enriched during fractional crystallization in a granite intrusion. Au was enriched during fractionation from a monzogranite to a highly fractionated alkali-feldspar granite. Similar enrichment behavior for other metals implies that no gold-enriched precursor melt is required and fractional crystallization can enrich the Au concentration to economic levels. The low content of accessory oxides and sulfides, the absence of early Clbearing fluids, the volatile content in the melt, and a prolonged crystallization constitute important factors for extensive metal enrichment during crystal fractionation. These characteristics play a crucial role in felsic, highly fractionated plutons and their associated deposits such as intrusion-related Au deposits. The gold enrichment during fractionation also implies that Au is directly sourced from the granites.

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Section: Geology Of the Timbarra Pluton And Sample Descriptionmentioning

confidence: 99%

Section: Geology Of the Timbarra Pluton And Sample Descriptionmentioning

confidence: 99%

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Gold and metal enrichment in natural granitic melts during fractional crystallization

Mustard

Ulrich

Kamenetsky

et al. 2006

Geol

Self Cite

102

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“…The liquid-bismuth collector model proposed by Douglas et al (2000) shows that there is a strong partition of gold into liquid bismuth from a hydrothermal fluid at 300°C; as much as 20 wt.% gold may be dissolved into the liquid bismuth. Those elements thus behave in a very compatible mode in a hydrothermal fluid, as advocated by Maloof et al (2001) and Mustard (2001) in some natural occurrences. It is worth noting here that AuCl 2 -dominates at high temperature (>290°C) and high salinity (>4 wt.% NaCl), whereas Au(HS) 2 -is stable at low-temperature and lowsalinity conditions (Large et al 1988).…”

Section: Mechanisms Of Ore Mineralizationmentioning

confidence: 76%

HYDROTHERMAL As Bi MINERALIZATION IN THE NAKDONG DEPOSITS, SOUTH KOREA: INSIGHT FROM FLUID INCLUSIONS AND STABLE ISOTOPES

Shin¹,

Park²,

Lee³

et al. 2004

The Canadian Mineralogist

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At the Nakdong As-Bi deposits, South Korea, Cambro-Ordovician sedimentary sequences are cut by numerous dykes of quartz monzodiorite and porphyritic granite. In the deposit, stage I involves arsenic mineralization, chiefly associated with arsenopyrite, pyrite, sphalerite and chalcopyrite, whereas bismuth mineralization characterizes stage II, with the coprecipitation of pyrrhotite, chalcopyrite, galena, bismuth, bismuthinite, cosalite, matildite, schirmerite, Au-Ag alloy, and argentite. The mineralization was initiated with the introduction of heterogeneous fluids of high salinity, presumably owing to the prominence of Ca, Mg, Na and K. At stage II, fluid immiscibility, which led to bismuth mineralization, produced (halite ± sylvite)-bearing highsalinity fluids of 27.6 to 49.3 wt.% NaCl equivalents, as well as low-salinity vapor-rich fluids. The homogenization temperatures of mineralizing fluids decreased only slightly from stage I, 283-416°C, to stage II, 222-395°C. A decrease in 18 O as well as 13 C in going from calcite in fresh limestone (␦ 18 O in the range +17.5 to +22.4‰, ␦ 13C in the range +2.3 to +4.4‰) to silicified limestone (␦ 18 O in the range +13.3 to +18.3‰, ␦ 13 C in the range -2.5 to +1.3‰) were promoted not only by Rayleigh volatilization, but also by fluid-rock interaction, with the influx of magmatic fluids into carbonate rocks during the mineralization process. The fluid-rock interaction contributed to the CO 2 and CH 4 components in type-III fluids and also to the Ca-enrichment in type-I fluid inclusions. The prevailing species of sulfur in the mineralizing fluids is estimated to have been H 2 S. The ␦ 34S H2S values obtained from the sulfide minerals increased from stage I, +3.2 to +4.4‰, to stage II, +4.1 to +4.8‰, values typical of magmatic sulfur, and the temperatures of homogenization of fluid inclusions increased as well. The decrease of sulfur fugacities, from 10 -9.1 -10 -6.4 atm at stage I to 10 -15.7 -10 -9.2 atm at stage II, through sulfide precipitation and H 2 S loss, induced the destabilization of bisulfide complexes and characterized the change of mineral stabilities from arsenopyrite -pyrite -sphalerite to bismuthinite -native bismuth assemblages.

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“…Reduced intrusion-related gold -ore systems are frequently encountered in many countries and regions. For example, in Canada, these deposits are Dublin Gulch, Scheelite Dome, Clear Creek that are localized within the Tombstone gold belt [4][5][6], while in the USA; they are the reduced Fort Knox gold systems [7]. Within these gold -ore targets native bismuth and bismuthcontaining sulphosalts display late paragenesis and are represented by typical alloys with Te, Pb, Sb and Au.…”

Section: Resultsmentioning

confidence: 99%

First native silica findings in bismuth from garnet skarns of Ribny Log - 2 gold ore target in Topolninsk ore deposit (Gorny Altai)

Cherkasova¹,

Timkin²,

Savinova³

2015

IOP Conf. Ser.: Earth Environ. Sci.

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kzzz@inbox.ruAbstract The nanomineralogic investigation results of ore minerals in metasomatites (garnet skarns) of Ribny Log-2 gold ore in Topolninsk ore deposit (Gorny Altai) revealed the native silica impurities (Si) of 1 -5 nm within the grains of native bismuth (Bi). Polished sections were examined by using Tescan Vega 3 scanning electron microscope (SEM) with Oxford energy-dispersive spectrometer at the

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Granite-hosted gold mineralization at Timbarra, northern New South Wales, Australia

Cited by 45 publications

References 0 publications

Gold and metal enrichment in natural granitic melts during fractional crystallization

Gold and metal enrichment in natural granitic melts during fractional crystallization

HYDROTHERMAL As Bi MINERALIZATION IN THE NAKDONG DEPOSITS, SOUTH KOREA: INSIGHT FROM FLUID INCLUSIONS AND STABLE ISOTOPES

First native silica findings in bismuth from garnet skarns of Ribny Log - 2 gold ore target in Topolninsk ore deposit (Gorny Altai)

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