Constraints on the genesis of gold mineralization at the Homestake Gold Deposit, Black Hills, South Dakota from rhenium–osmium sulfide geochronology

Morelli, R.M.; Bell, Chris C.; Creaser, Robert A.; Simonetti, Antonio

doi:10.1007/s00126-010-0284-9

Cited by 78 publications

(35 citation statements)

References 45 publications

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“…These Re-Os ages on arsenopyrite indicate that mineralization is pre-metamorphic and that 2632 Ma amphibolite-grade metamorphism at ∼600°C and 1-5 kbar did not reset the 2663 Ma arsenopyrite Re-Os system in sample 316665. These observations are similar to those implying retention of Re-Os age information in arsenopyrite through younger metamorphism at the Proterozoic Homestake deposit, North Dakota, USA (Morelli et al 2010). In the latter case, the Re-Os system in arsenopyrite was found to record formation at 1736 Ma, despite metamorphic conditions estimated at 500-550°C and 2-4 kbar during later stages of regional metamorphism (<1736-1690 Ma) and crustal temperatures that remained above 350°C for 1500-1300 Ma (Morelli et al 2010).…”

Section: Age Of Mineralizationsupporting

confidence: 83%

Metallogeny of the Marco zone, Corvet Est, disseminated gold deposit, James Bay, Quebec, Canada

et al. 2012

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The Corvet Est gold deposit is hosted by Archean rocks of the Superior Province in the James Bay region, northern Quebec, Canada. The Marco zone is hosted by amphibolite-grade, strongly foliated volcanic rocks and consists of disseminated gold, with an apparent thickness ranging from 1.8 to 39.5 m and gold grades up to 23 g·t -1 over 1 m, that is continuous along strike for ∼1.3 km. The lithotectonic sequence comprises footwall basaltic andesite amphibolite overlain by a lenticular unit of metadacite and then by hanging-wall basaltic andesite amphibolite, all intruded by quartz-feldspar porphyry dikes. Dacite, basaltic andesite amphibolite, and quartz-feldspar porphyry show a calc-alkaline to transitional affinity and plot in the plate margin arc basalt field, with typical volcanic arc trace element patterns. Mineralization consists of pyrite, arsenopyrite, pyrrhotite, chalcopyrite, and gold, disseminated in deformed dacite, in andesite amphibolite, and in quartz-feldspar porphyry dikes. Dacite and andesite display weak alteration characterized by silicification. Native gold forms inclusions in metamorphic quartz, garnet, feldspar, arsenopyrite, and pyrite or free grains interstitial to quartz, feldspar, pyrite, chalcopyrite, and arsenopyrite. Free gold in late quartz veins cut the sericitized metamorphic fabric. Inclusion and interstitial native gold within minerals annealed during metamorphism shows that gold mineralization is pre-to syn-metamorphic, with some gold remobilized in later veins. Rhenium-osmium dating of arsenopyrite yields an isochron age of 2663 ± 13 Ma for mineralization and a weighted average model age of 2632 ± 7 Ma for arsenopyrite formed during peak metamorphism. The ∼2663 Ma arsenopyrite has a low initial 187 Os/ 188 Os of 0.19 ± 0.10, suggesting a juvenile crust or a mantle Os source. The sulfur isotope composition of Marco zone pyrite and arsenopyrite shows that sulfur could have been leached from its volcanic host rocks or from reduction of Archean seawater. The Corvet Est deposit is interpreted to be an orogenic gold deposit (2663 Ma) deformed and recrystallized during amphibolite-grade metamorphism (2632 Ma).Résumé : Le gîte aurifère Corvet Est est encaissé dans des roches archéennes de la Province du Supérieur dans la région de la baie James, Nord du Québec, Canada. La zone Marco est encaissée dans des roches volcaniques, intensément foliées, au grade des amphibolites et elle comprend de l'or disséminé dans une zone d'une épaisseur apparente variant de 1,8 à 39,5 m; la teneur de l'or atteint 23 g/t sur 1 m et la zone est continue le long de la direction sur environ 1,3 km. La séquence lithotectonique comprend une andésite basaltique amphibolitisée dans l'éponte inférieure recouverte d'une unité lenticulaire de métadacite puis d'une andésite basaltique amphibolitisée dans éponte supérieure; le tout est recoupé par des dykes porphyriques de quartz-feldspath. La dacite, l'andésite basaltique amphibolitisée et le porphyre quartz-feldspath montrent une affinité calco-alcaline à transitionn...

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Section: Age Of Mineralizationsupporting

confidence: 83%

Metallogeny of the Marco zone, Corvet Est, disseminated gold deposit, James Bay, Quebec, Canada

et al. 2012

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“…The Re-Os technique has been successfully applied to molybdenite and a number of other sulphides (Stein et al 2000(Stein et al , 2001Creaser 2001a, 2001b). In particular, arsenopyrite has been recognized as suitable for Re-Os dating of gold deposits due to the widespread occurrence of arsenopyrite in such deposits, and the close paragenetic association of arsenopyrite and gold (Morelli et al 2005(Morelli et al , 2010. Arsenopyrite typically contains low concentrations of Re (1-100 ppb) and parts-per-trillion (ppt) Os concentrations.…”

Section: Re-os Geochronologymentioning

confidence: 99%

“…The Re-Os isotopic analyses were performed at the Radiogenic Isotope Facility of the Department of Earth and Atmospheric Sciences, University of Alberta. The analytical protocol follows that described by Morelli et al (2010). Isochron regression used Isoplot v3.00 (Ludwig 2003) and the 187 Re decay constant of Smoliar et al (1996).…”

Section: Re-os Geochronologymentioning

confidence: 99%

Re-Os geochronology of gold mineralization in the Fawakhir area, Eastern Desert, Egypt

Zoheir

Creaser

Lehmann

2014

International Geology Review

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We report the first Re-Os data on gold-associated arsenopyrite from mesothermal gold-quartz veins in the ancient Egyptian Fawakhir-El Sid gold mining district in the central Eastern Desert. This mining district has an~5000-yearold history and is displayed in the Turin Papyrus Map (about 1150 BC), which is widely acclaimed as the world's oldest geographic map, as well as the oldest geologic and mine map. The Fawakhir-El Sid district is part of a regional NNWtrending shear corridor (15 km wide) that hosts several other historic gold mines associated with left-lateral wrench structures and related granite intrusions. Vein-style gold mineralization is hosted within and at the margin of an I-type and magnetite-series monzogranite, the Fawakhir granite intrusion, and a Pan-African (~740 Ma) ophiolite sequence. The ore mineralogy of the mineralized quartz veins includes pyrite-arsenopyrite-pyrrhotite-sphalerite-galena-chalcopyrite-electrum plus a number of tellurides of Ag, Au, and Bi. The 187 Re/ 188 Os versus 187 Os/ 188 Os regression on 5 points of arsenopyrite gives an age of 601 ± 17 Ma with an initial 187 Os/ 188 Os of 0.24 ± 0.07 (2 σ; MSWD = 17). This age coincides within error with the U-Pb age on zircon from the Fawakhir monzogranite (598 ± 3 Ma). The age coincidence and the hydrothermal Te and Bi metal signature suggest a foremost role of granite-related fluids in the quartz-vein system.

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“…At Silvermines, massive pyrite from the B Zone orebody (samples B18, B15) was chosen (sample descriptions in Appendix DR1 in the Data Repository). All pyrite separates were produced and analyzed using the procedures described by Morelli et al (2010; additional details are described in Appendix DR2). We analyzed 12 pyrite separates from the Lisheen sample, with Re and Os concentrations of 2-8 ppb and 15-280 ppt, respectively.…”

Section: Re-os Geochronologymentioning

confidence: 99%

Re-Os dating of pyrite confirms an early diagenetic onset and extended duration of mineralization in the Irish Zn-Pb ore field

Hnatyshin

Creaser

Wilkinson

et al. 2015

Geology

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The Irish Midlands region contains one of the world's largest hydrothermal Zn-Pb ore districts, but uncertainty exists in the timing of mineralization relative to host rock ages. Consequently, genetic models for ore formation are poorly constrained and remain controversial. Here we use Re-Os geochronology to show that ore-stage pyrite from the Lisheen deposit formed at 346.6 ± 3.0 Ma, shortly after host rock deposition. Pyrite from the Silvermines deposit returns an age of 334.0 ± 6.1 Ma, indicating that at least some mineralization occurred during later burial. These age determinations show that the much younger paleomagnetic ages reported for the Irish Zn-Pb deposits reflect remagnetization during the Variscan orogeny, a process that we suggest affects paleomagnetic dating more widely. The Re-Os ages overlap with the ages of lower Carboniferous volcanic rocks in the Midlands, which are the product of magmatism that has been invoked as the driving force for hydrothermal activity. The relatively low initial Os ratios for both Lisheen (0.253 ± 0.045) and Silvermines (0.453 ± 0.006) are compatible with derivation of Os from these magmas, or from the Caledonian basement that underlies the ore deposits.

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Constraints on the genesis of gold mineralization at the Homestake Gold Deposit, Black Hills, South Dakota from rhenium–osmium sulfide geochronology

Cited by 78 publications

References 45 publications

Metallogeny of the Marco zone, Corvet Est, disseminated gold deposit, James Bay, Quebec, Canada

Metallogeny of the Marco zone, Corvet Est, disseminated gold deposit, James Bay, Quebec, Canada

Re-Os geochronology of gold mineralization in the Fawakhir area, Eastern Desert, Egypt

Re-Os dating of pyrite confirms an early diagenetic onset and extended duration of mineralization in the Irish Zn-Pb ore field

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