Allochthonous prodeltaic sediment facies in the Lower Cretaceous at the Tantallon M-41 well: Implications for the deep-water Scotian Basin
Bibliographic record
Abstract
Abstract Lower Cretaceous shelf-margin deltas in the Scotian Basin prograded across a deep outer-shelf platform and may have supplied sand to the deep-water Scotian margin. Conventional core from the Tantallon M-41 well was used to evaluate sediment facies and evidence for the transfer of deltaic sand to deep water. Two cores with shallow-water lithofacies show sediment deformation structures, resulting from surficial debris flow and deeper seated landsliding of deltaic sediment, interpreted by a comparison with modern sea-floor piston cores. Both mass-movement types produced a basal strongly foliated mudstone. Such allochthonous blocks create potential pitfalls in interpretation of paleowater depth from sedimentary structures in conventional core and microfossils in ditch cuttings. Autochthonous sediment on the deep outer-shelf platform is a distinctive red-brown mudstone with rare turbidite sandstone beds. The deepest core consists of thin-bedded sandstone turbidites showing Bouma Tb-c-d intervals and fading ripples characteristic of overbank settings, deposited on a high adjacent to 50–150-m (160–500-ft)-deep channels. These sandstones provide direct evidence that sand was transferred through channels into deep water in the Early Cretaceous. Sandy turbidity currents were sourced both by prodeltaic failure and transformation and by hyperpycnal flow from the mountainous rivers that supplied sediment to the Scotian 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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".