The Otish Basin: basin evolution and formation of the Camie River deposit, Quebec
Bibliographic record
Abstract
The Otish Basin of central Quebec hosts over thirty uranium prospects, including the Camie River prospect that is located near the unconformable contact between the graphite-bearing, metamorphic basement of Archean age and the overlying basinal sedimentary rocks of the Otish Supergroup. The maximum age of the basin, constrained by the age of the unconformably-underlying Mistassini dyke swarm, is 2515 } 3 Ma. Following the deposition of the Otish Supergroup, the basin was intruded by the Otish Gabbros, a suite of olivine-tholeiitic dykes and sills of near-liquid compositions (Group 1) and cumulate rocks (Group 2). Uranium-lead zircon ages from the Otish Gabbros indicate the minimum age of the Otish Basin is ca. 2.17 Ga. The Otish Basin was also intruded by the Matoush dyke, interpreted to be younger than the Otish Gabbros. The least altered samples of the Matoush dyke have mineralogy and trace element systematics, such as highly fractionated REE patterns, similar to lamprophyric rocks and are distinct from the tholeiitic to weakly trace element-enriched Otish Gabbros. This, therefore, indicates that the Otish Basin was affected by at least two igneous events. The uranium mineralization formed after the peak diagenetic alteration of the Otish Supergroup. During peak diagenetic conditions, early albitic sandstone cement was largely replaced by K-feldspar. The feldspathic cement was subsequently partially replaced by a green muscovite alteration. The increase in Na2O concentrations of the feldpsathiccemented sandstones towards the base of the sedimentary sequence is noteworthy. Uraninite and brannerite are the principal uranium minerals at the Camie River prospect. Molybdenite grains, intergrown with uraninite, yield a Re-Os model age of 1724 } 4. 9 Ma that is indistinguishable from the previously published uraninite ages. The age of mineralization is significantly younger than the age of the Otish Gabbros, indicating that the uranium mineralization postdates sedimentation by ?450 m.y. The overlapping Sm-Nd isotopic ages from Otish Gabbros suggest the main uranium mineralization was locally accompanied by resetting of the Sm-Nd system and LREE mobility in the gabbros. The age of mineralization in the Otish Basin is similar to the age of polymetallic mineralization of the Huronian Supergroup, suggesting the ca. 1.7 Ga hydrothermal activity may have been a regional phenomenon affecting the southern Superior Province.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".