Paleoproterozoic Age Relationships in the Three Bluffs Archean Iron Formation-Hosted Gold Deposit, Committee Bay Greenstone Belt, Nunavut, Canada
Bibliographic record
Abstract
Research Article| July 01, 2010 Paleoproterozoic Age Relationships in the Three Bluffs Archean Iron Formation-Hosted Gold Deposit, Committee Bay Greenstone Belt, Nunavut, Canada* T. Davies; T. Davies 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar J.P. Richards; J.P. Richards † 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada †Corresponding Author: E-mail: Jeremy.Richards@ualberta.ca Search for other works by this author on: GSW Google Scholar R.A. Creaser; R.A. Creaser 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar L.M. Heaman; L.M. Heaman 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar T. Chacko; T. Chacko 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar A. Simonetti; A. Simonetti 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar J. Williamson; J. Williamson 2Committee Bay Resources Ltd., #220, 9797 45 Avenue, Edmonton, Alberta, T6E 5V8, Canada Search for other works by this author on: GSW Google Scholar D.W. McDonald D.W. McDonald 2Committee Bay Resources Ltd., #220, 9797 45 Avenue, Edmonton, Alberta, T6E 5V8, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information T. Davies 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada J.P. Richards † 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada R.A. Creaser 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada L.M. Heaman 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada T. Chacko 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada A. Simonetti 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada J. Williamson 2Committee Bay Resources Ltd., #220, 9797 45 Avenue, Edmonton, Alberta, T6E 5V8, Canada D.W. McDonald 2Committee Bay Resources Ltd., #220, 9797 45 Avenue, Edmonton, Alberta, T6E 5V8, Canada †Corresponding Author: E-mail: Jeremy.Richards@ualberta.ca Publisher: Canadian Institute of Mining, Metallurgy and Petroleum Received: 07 Oct 2009 Accepted: 31 Mar 2011 First Online: 02 Mar 2017 © 2011 Canadian Institute of Mining, Metallurgy & Petroleum Exploration and Mining Geology (2010) 19 (3-4): 55–80. https://doi.org/10.2113/gsemg.19.3-4.55 Article history Received: 07 Oct 2009 Accepted: 31 Mar 2011 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation T. Davies, J.P. Richards, R.A. Creaser, L.M. Heaman, T. Chacko, A. Simonetti, J. Williamson, D.W. McDonald; Paleoproterozoic Age Relationships in the Three Bluffs Archean Iron Formation-Hosted Gold Deposit, Committee Bay Greenstone Belt, Nunavut, Canada. Exploration and Mining Geology 2010;; 19 (3-4): 55–80. doi: https://doi.org/10.2113/gsemg.19.3-4.55 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyExploration and Mining Geology Search Advanced Search Abstract The Three Bluffs gold deposit is located in the Committee Bay greenstone belt, which forms part of the Rae domain of the western Churchill province, Nunavut, Canada. Gold mineralization is hosted by iron formation of the Neoarchean volcanosedimentary Prince Albert Group, and is associated with silicification (quartz veining) and sulfidation of magnetite and other Fe-rich minerals.Conventional U-Pb zircon dating of a conformable dacite unit within the volcanosedimentary host-rock sequence and a crosscutting diorite intrusion confirm a ~2.7 Ga age for deposition of the supracrustal package.U-Pb monazite dates and Pb isotopic analyses of sulfides were obtained by laser ablation–multicollector–inductively coupled plasma–mass spectrometry (LA-MC-ICP-MS). A subset of U-Pb monazite (1813.8 ± 8.7 Ma) and Re-Os arsenopyrite (1822 ± 21 Ma) dates, combined with a Pb-Pb secondary errorchron age for pyrite and arsenopyrite (1829 ± 77 Ma), suggest that gold mineralization associated with sulfidation of the iron formation occurred at ~1815 Ma, prior to high-grade (upper amphibolite facies) tectonometamorphism in the Three Bluffs area (D2TB/(M2TB).An ~1815 Ma age for deposit formation is broadly consistent with evidence from elsewhere in the western Churchill province and to the southwest in Manitoba and Saskatchewan for a late Trans-Hudson (1.9–1.8 Ga) gold mineralizing event. The majority of U-Pb monazite ages form a second population at 1780.6 ± 4.2 Ma, similar to the age of the majority of Re-Os arsenopyrite analyses (1763 ± 11 Ma). These dates are thought to reflect the timing of peak M2TB metamorphism. 40Ar/39Ar dating of amphibole, biotite, and muscovite yielded plateau ages ranging from 1723.8 ± 9.0 Ma to 1710 ± 17 Ma, which are interpreted to record the timing of postpeak metamorphic cooling to below the respective closure temperatures for Ar diffusion in these minerals. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".