Hydrothermal alteration of fractured Carboniferous sedimentary rocks along the Cobequid Fault Zone, western Nova Scotia
Bibliographic record
Abstract
The Cobequid Fault Zone in northwestern Nova Scotia hosts the famous Londonderry iron deposit and smaller magnetite, base metal sulfide and barite deposits. The paragenetic sequence of hydrothermal veins cutting Tournaisian Horton Group sandstones and shales in the western part of the Cobequid Fault Zone was investigated from cross-cutting relationships in the field and from SEM backscattered electron images of polished thin sections. In hydrothermal veins in the Lynn Road area east of Parrsboro, the general paragenesis is: albite ± quartz ± chlorite ? biotite ? calcite ? pyrite and other sulfides ? supergene enrichment. Farther west, between Parrsboro and West Advocate, the general paragenesis is: quartz ± chlorite ? Fecarbonates, minor sulfides, calcite and synchysite ? supergene enrichment. Chlorite formation temperatures were higher at West Advocate (~215°C) than elsewhere (~165°C). In the area between Parrsboro and Lynn Road, 334 Ma lamprophyric subvolcanic intrusions include magmatic allanite, calcite and sulfides and these minerals are also found in veins in the Lynn Road area. Widespread veins of Fe-carbonates, magnetite and sulfides (Fe, Cu, Zn) were emplaced at ~323 Ma and were subsequently enriched by supergene alteration. Hydrothermal REE minerals in sedimentary host rocks are quite different from those in adjacent granite plutons, suggesting the importance of local derivation of REE and the role of fluorine in REE mobility in igneous rocks.
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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".