AMORPHOUS CARBON AND METALLIC NANOPARTICLES IN OROGENIC GOLD DEPOSITS, ABITIBI SUBPROVINCE (CANADA)
Bibliographic record
Abstract
Abstract Amorphous carbon (C(am)) and metallic nanoparticle formation in orogenic gold systems have recently been associated with a sequence of fluid decompression and cooling steps. Nevertheless, C(am) phases and nanoparticles identified in orogenic gold systems remain poorly documented in economic gold veins. Here, we investigate two hydrothermal events, recorded in the southern Abitibi subprovince (Canada), associated with gold deposit formation (Goldex, ~1 g/t Au; and Plug #4, ~7 g/t Au). The first auriferous hydrothermal event comprises pyrite-hosted, nm- to µm-sized, polymetallic inclusions. This event is overprinted by a texturally late, post-ore, regional hydrothermal event preserved as calcite Au-Ag-Te-Bi microveinlets mostly visible in pyrite. Transmission electron microscopy and nanoscale energy dispersive spectroscopy of eight foils targeting inclusions and microveinlets in pyrite from both hydrothermal events reveal that (1) polymetallic inclusions have sharp internal boundaries with the pyrite host, and formed at equilibrium, whereas (2) calcite Au-Ag-Te-Bi microveinlets in pyrite show open-space infill by C(am) (C3+XON) that forms interstitial, <300-nm-thick aggregates between the BiTe-Au calcite interface and pyrite host. The amorphous phase contains subrounded to rounded inclusions of BiTe(s), tsumoite nanoparticles between 12 and 50 nm in diameter. We propose that cooling of hydrothermal fluids, rich in H2Te–II(aq), BiIIICl3(aq), and BiIII(OH)3(aq), led to the precipitation of BiTe(s) nanoparticles within C(am). This post-ore process during late-stage calcite deposition along the CO2-CH4 redox buffer involved coupled fluid redox reactions. Fluid redox processes are important factors that could at least partially explain the formation of metallic nanoparticles and commonly undetected C(am) phases associated with post-ore hydrothermal activity.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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 teacher head, 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".