Alteration Pattern and Fluid Inclusions of Gold-Bearing Quartz Veins
Bibliographic record
Abstract
Systems of auriferous quartz veins occur in Archean granitic rocks within 1.6 km of the Wawa greenstone belt, 80 km northeast of Wawa, Ontario. The vein system at the Renabie mine strikes west for approximately 850 m, dips steeply to a depth of at least 950 m, and hosts orebodies up to 30 m wide and 210 m long. The six vein systems at the Braminco prospect strike north to northwest, dip steeply, and are up to 20 m wide. Alteration of feldspar to quartz + calcite + white mica + albite, and of biotite + amphibole to chlorite, intensifies within 2 to 4 m of quartz vein systems bearing native gold. Mass balance calculations suggest that the alteration of granitic rocks added K, CO2 + H20, Rb, and Ba and removed Na. Three types of primary fluid inclusions coexist in quartz from the auriferous vein systems. Type I, the most abundant ype, is an aqueous olution with 10 to 25 vol percent CO2 with density of 0.75 g/cm3; homogenization temperatures range from 220 ø to 360øC. Type II is nearly 100 vol percent liquid CO2, with a density of 0.95 g/cm 3. Type III, the least abundant type, is an aqueous liquid with 10 to 50 vol percent H20 gas; homogenization temperatures range from 120 ø to 220øC. Apparent salinities of types I, II, and III, based on clathrate and ice melting points, are estimated to be 4 to 8, 0, and 11 to 14 equiv wt percent NaCI, respec-tively. The preferred interpretation is that the gold-bearing quartz veins formed from CO2-1aden fluids of less than 10 equiv wt percent NaCI during regional greenschist metamorphism of granitic rocks. The three types of fluid inclusions may represent two or three different gen-erations of fluids trapped over a range of temperature and pressure. Another possibility is that the fluid inclusions represent samples of a fluid comprised of immiscible CO2 and NaCI-H20 phases, entrapped during quartz crystallization. The source of the gold is not known.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".