Shale compositional trends in the Cenomanian–Turonian Cretaceous Western Interior Seaway: facies and sequence stratigraphic models
Bibliographic record
Abstract
ABSTRACT Predictive facies and sequence-stratigraphic models (Hart 2015, 2016) for fine-grained sediment deposition associated with a peak transgression in an epeiric seaway have been tested here using elemental, mineralogical, TOC, and wireline log data. Our samples were collected from close to the Cenomanian–Turonian boundary from five widely dispersed locations (Texas, New Mexico, Colorado, Alberta, Manitoba). We collected data from a range of lithotypes (shales, marlstones, and limestones) from both core and exposures to test the models. Profiles of major elements (Si, Al, Ca, etc.) and TOC show distinctive trends depending on the relative proximity of the location to the shoreline at peak transgression. Siliciclastic minerals (and hence elements such as Si, Al, K) dominate the section in our most proximal location whereas peak transgression was dominated by deposition of pelagic carbonates in distal locations. Organic-carbon content is variably related to sediment composition, again depending on the relative proximity of the location to the shoreline at peak transgression. TOC is highest in marlstones (deposited where pelagic and siliciclastic sediments mixed) and decreases both in basin-center limestones and in proximal, siliciclastic shales.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".