Mineralogical and chemical characterization of Mississippi Valley–type mineralization in British Columbia and Alberta, Canada: Implications for ore-forming processes
Bibliographic record
Abstract
A comprehensive study of samples from MVT–type base-metal (Zn-Pb) deposits from across the Canadian Cordillera was done to compare and contrast features and assess their relevance in the context of sulphide mineralization. Petrography and supported CL imaging indicates early host rock dissolution to form secondary fine-grained dolostone during marine cementation is followed by multiple generations of dolomite cements (low T, fine-grained to coarser, higher T varieties) that overlaps with Zn-Pb sulphides which is succeeded by a later barren calcite stage. Ore-stage dolomite is often rich in Fe (<1.3 wt. % FeO) and hosts small sphalerite inclusions. Sphalerite-hosted fluid inclusions record Th values (77–214°C) and salinities (1–28 wt. % equiv. NaCl±CaCl2) that reflect fluid mixing with no single fluid type related to sulphide mineralization. In situ SIMS δ18OVSMOW data for dolomite and calcite (13 to 33‰) suggest involvement of several fluids (i.e., seawater, basinal, meteoric) over a large temperature range at varying fluid-rock ratios. In situ SIMS δ34SVCDT data for sphalerite and pyrite indicate a large variation (8 to 33‰), but with smaller ranges (<2 to 3‰) for the settings studied, and suggest reduced S was produced dominantly via TSR processes from homogeneous sulphur reservoirs. Together the datasets suggest involvement of several fluids in the mineralizing process with mixing of a S-poor, metal-bearing fluid with a metal-poor, S-bearing fluid.
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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 | 0.004 | 0.004 |
| Science and technology studies | 0.003 | 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) | 0.001 | 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".