Early Cretaceous continental-scale sediment routing, the McMurray Formation, Western Canada Sedimentary Basin, Alberta, Canada
Bibliographic record
Abstract
Alternative depositional models for the Early Cretaceous McMurray Formation between a dominantly continental and marginal marine settings remain a controversial topic. The source-to-sink model can be inverted to reconstruct ancient sediment-routing systems by utilizing methods to estimate ancient drainage basins, which can contribute to understanding of sediment routing and testing of alternative depositional models. New detrital zircon U-Pb ages from 31 samples were analyzed to identify source terranes of the McMurray Formation and the overlying Wabiskaw Member of the Clearwater Formation to test first-generation alternative sediment-routing models and estimate maximum depositional ages. In total, 9729 new concordant U-Pb ages identified multiple source terranes for the McMurray Formation within an interpreted continental-scale paleodrainage basin that extended from the SW to SE United States and eastern Canada. The paleodrainage basin then expanded to include the Western Cordillera arc system within the overlying Upper Mannville Group. Multidimensional scaling and mixing models independently support a paleo-upstream mixing of primary and recycled sources in the McMurray Formation axial system in the United States and a paleo-downstream confluence between this axial system and east-derived sediment-routing systems in Canada, which display an evolution from bedrock-confined to alluvial morphology from the lower to middle-upper McMurray Formation. The current dataset constrains the maximum depositional age of the McMurray Formation to the latest Barremian to Aptian, with an age range from ca. 122 to 115 Ma, which is significantly younger than previously reported. Age estimates in the overlying Upper Mannville units from ca. 115 to 110 Ma statistically overlap with the McMurray Formation age, suggesting continuous Mannville deposition that lasted 10−12 m.y. or less.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.024 | 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 teacher head, 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".