Depositional age of the Douglas Formation, northern Saskatchewan, determined by Re-Os geochronology
Bibliographic record
Abstract
Rhenium-osmium geochronology of organic-rich shale of the Douglas Formation, northern Saskatchewan, yields a precise date of 1541 ± 13 Ma (2? uncertainty, Model 1 isochron), which is interpreted to be the depositional age of the samples. This result provides a robust determination for deposition of some of the youngest sedimentary rocks within the Athabasca Basin, and extends the confirmed duration of sedimentation by about 100 million years. The Re-Os date for the Douglas Formation (sequence 4) suggests that a substantive hiatus is recorded at the unconformity between rocks of sequence 3 and sequence 4. The Re-Os age is also similar to the oldest published ages of uranium mineralization within the deeper basin, suggesting that the onset of mineralization was broadly contemporaneous with deposition of the youngest sediments in the Athabasca Basin.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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) | 0.002 | 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".