Paleoproterozoic Age Relationships in the Three Bluffs Archean Iron Formation-Hosted Gold Deposit, Committee Bay Greenstone Belt, Nunavut, Canada

Davies, Troy A.; Richards, Jeremy P.; Creaser, Robert A.; Heaman, Larry M.; Chacko, Thomas; Simonetti, Antonio; Williamson, J.; McDonald, Dean

doi:10.2113/gsemg.19.3-4.55

Cited by 12 publications

(20 citation statements)

References 44 publications

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“…This inferred Paleoproterozoic gold metallotect potentially extends across Nunavut and into northern Manitoba and Saskatchewan ( Fig. 1; Davies et al, 2010). However, the western Churchill Province records a complex and protracted Archean to Proterozoic history that is punctuated by at least four temporally distinct orogenic events ( Fig.…”

Section: Unraveling the Western Churchill Province Paleoproterozoic Gmentioning

confidence: 92%

“…1.85 Ga, Meliadine, Carpenter et al, 2005; ca. 1.78 and 1.81 Ga, Three Bluffs, Davies et al, 2010) that are broadly correlative with the Trans-Hudson Orogeny. However, the absolute age of mineralization at these deposits remains somewhat equivocal owing to the difficulty of directly dating the introduction and subsequent remobilization of gold.…”

Section: Introductionmentioning

confidence: 93%

“…Notable exceptions include (1) Mesozoic gold districts situated at the cratonic margin bordering the North China craton, China (e.g., Li et al, 2012); (2) Paleoproterozoic, Mesoproterozoic, and Neoarchean-Paleozoic Lupa, Mpanda, and Niassa gold districts, respectively, which are hosted, in part, by reworked Archean crust at the Tanzanian cratonic margin (Bjerkgard et al, 2009;Lawley et al, 2013a, b;Kazimoto, 2014); and (3) Paleoproterozoic gold districts situated within the western Churchill Province, Canada (e.g., Three Bluffs, Davies et al, 2010;Meadowbank, Sherlock et al, 2004;Meliadine gold district, Carpenter et al, 2005). Gold at each of these exceptional districts postdates their host rocks, in some cases by over 1 billion years.…”

Section: Introductionmentioning

confidence: 99%

“…Section line for Figure with orogenic gold-style mineralization and occur as either greenstone-hosted auriferous quartz (± carbonate) veins and/ or banded iron formation (BIF)-hosted gold deposits (e.g., the past-producing Cullaton deposit, the operating Meadowbank deposit, Three Bluffs). The Paleoproterozoic metallotect is conventionally attributed to widespread reworking of the western Churchill Province during the Trans-Hudson Orogeny (1.9-1.8 Ga; e.g., Miller et al, 1994;Sherlock et al, 2004;Carpenter et al, 2005;Davies et al, 2010), which is the last major tectonothermal event to affect large swaths of the western Churchill Province (Fig. 2).…”

Section: Introductionmentioning

confidence: 99%

“…1.82 Ga, Three Bluffs; Davies et al, 2010) and U-Pb hydrothermal monazite ages from auriferous veins (i.e., 1.8-1.9 Ga, Meadowbank, Sherlock et al, 2004;ca. 1.85 Ga, Meliadine, Carpenter et al, 2005; ca.…”

Section: Introductionmentioning

confidence: 99%

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Unraveling the Western Churchill Province Paleoproterozoic Gold Metallotect: Constraints from Re-Os Arsenopyrite and U-Pb Xenotime Geochronology and LA-ICP-MS Arsenopyrite Trace Element Chemistry at the BIF-Hosted Meliadine Gold District, Nunavut, Canada

et al. 2015

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The gold endowment of the western Churchill Province is conventionally attributed to reworking and attendant metamorphism during the Trans-Hudson Orogeny (1.9-1.8 Ga). The Meliadine gold district is regarded as a type example of this inferred Paleoproterozoic gold metallotect and also represents one of Canada's largest emerging orogenic greenstone-and banded iron formation (BIF)-hosted gold districts (2.8 Moz contained Au in reserves and total resource of 5.8 Moz Au). The largest gold deposits are cospatial with the Pyke fault and associated quartz (± ankerite) veining, which cuts Neoarchean (ca. 2.66 Ga) plutonic and supracrustal rocks comprising the Rankin Inlet greenstone belt.Meliadine gold occurs as inclusions within idioblastic arsenopyrite crystals, at sulfide crystal boundaries, and/ or as sulfide fracture fills in hydrothermally altered, sulfidized, and veined BIF. Clusters of gold, Bi-Mo telluride, chalcopyrite, and galena inclusions characterize high-grade ore zones and are spatially associated with sieve-textured arsenopyrite domains. These microtextural relationships suggest that incipient sulfide recrystallization liberated gold, which, along with other precious and base metals, was redistributed during late, fluidassisted and deformation/metamorphic-driven remobilization. Late precious and base metal enrichment is also demonstrated by in situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) arsenopyrite mapping. Hydrothermal xenotime crystals occur with gold in low-strain microtextural sites and yield U-Pb ages at ca. 1.86 Ga, suggesting that remobilization was concomitant with Trans Hudson orogenesis.New Re-Os arsenopyrite model ages range from 2.3 to 1.8 Ga and document a hitherto unrecognized, pre-1.86 Ga hydrothermal activity. The range of Re-Os model ages tends to support partial open-system behavior and/or mixing of disparate arsenopyrite generations that are evident from microtextural observations and in situ LA-ICP-MS element mapping. Replicate analyses of the two most rhenium rich arsenopyrite samples yield reproducible Re-Os model ages at ca. 2.27 and 1.90 Ga. These rhenium-rich samples are also gold poor and likely yield ages that predate gold remobilization and subsequent enrichment along arsenopyrite crystal boundaries and fractures. We suggest that pre-1.86 Ga hydrothermal activity was likely critical to the gold endowment of the district, but is obscured by reworking during the later stages of the Trans-Hudson Orogeny at 1.86 Ga. If correct, these new ages imply that the Paleoproterozoic gold metallotect, which is recorded across the western Churchill Province, in fact comprises multiple, temporally distinct gold events. Differentiating between disparate Paleoproterozoic gold events represents a critical step for effective mineral exploration in the western Churchill Province and at other reworked Archean terranes.

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Section: Unraveling the Western Churchill Province Paleoproterozoic Gmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 93%