Detrital mineral provenance analyses from the Cretaceous McMurray Formation, Alberta and the Holocene Portneuf river delta, North Shore of Quebec
Bibliographic record
Abstract
The dispersion of sandy sediment by the early Cretaceous Sable River has been further investigated by detailed mineralogical study of (a) two samples from the Aptian McMurray Formation of Alberta and (b) a Holocene deltaic deposit on the North Shore of the St Lawrence Estuary. Samples from Alberta were to test the hypothesis that Aptian diversion of the Sable River led to it flowing to the Western Interior Seaway, contributing sand to the McMurray Formation. Pb-isotopes in K-feldspar show that most of the first cycle feldspars in the McMurray Formation were derived from the local Trans-Hudson Orogen. The heavy mineral assemblage, particularly the abundance of staurolite and paucity of chromite, is different from that of the Sable River. The Holocene deltaic sand was analysed to identify distinctive heavy minerals from that part of the Grenville terrane. Garnets are similar to enigmatic garnets from the Jurassic of the Mohawk B-93 well, where Pb-isotopes on K-feldspar also suggest a Grenville source. Titania minerals with abundant quartz inclusions, known from both the Scotian Basin and the McMurray Formation, were not present in the Holocene sample and their provenance significance remains enigmatic.
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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 | 0.003 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".