Sulphur isotope geochemistry and Re-187-Os-187 temporal constraints on the formation of polymetallic iron-oxide-dominated deposits in the Great Bear magmatic zone, NWT, Canada
Bibliographic record
Abstract
The Great Bear magmatic zone (GBnnz) contains several examples of iron oxide copper-gold (IOCG) mineralization including the Sue-Dianne and NICO deposits and other prospects like DAMP. The delta S-34 values in pyrite, arsenopyrite and chalcopyrite from NICO range from 2.5 parts per thousand to 6.7 parts per thousand; pyrite from DAMP varies from - 0.1 parts per thousand to 5 parts per thousand. Conversely, chalcopyrite from Sue Dianne delta S-34 has a dominantly negative signature ranging from - 7.7 parts per thousand to 1 parts per thousand. The preliminary delta S-34 data have values close to 0 parts per thousand suggesting an important magmatic contribution to the formation of IOCGs in the GBmz. However, some of the relatively S-34-enriched (> 5 parts per thousand) and -depleted (<-5 parts per thousand) signatures could also indicate that some of the sulphur found in these systems is derived from non-magmatic sources. In addition, Re-187-Os-187 dating of two molybdenite samples was carried out on NICO deposit. One sample represents a late stage of mineralization (NM3) within the main ore zone and has an age of ca.1865. The second sample formed ca.1877 and was collected from a U +/- Cu-Mo- rich zone within the Southern Breccia. The Re-187-Os-187 molybenite ages from NICO deposit also suggest a magmatic origin as they are correlative (within error) with plutonic events emplaced between 1866 Ma and 1875 Ma in this area.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 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".