Sediment Dynamics and Stratigraphic Architecture of a Lower Silurian Storm-dominated Carbonate Ramp, Anticosti Island, Québec, Canada
Bibliographic record
Abstract
The upper Llandovery succession across the Jupiter-Chicotte formational contact on Anticosti Island, Québec, allows us to study the sediment dynamics and stratigraphic architecture of a storm-dominated, carbonate ramp. The Anticosti paleotropical ramp was slowly subsiding and recording significant changes in sea level in a far field glacial setting during the early Telychian. Three facies associations, grouping nine facies, are recognized along the E-W outcrop belt, and from top to bottom as the: (FA-1) encrinitic carbonate facies, (FA-2) mixed siliciclastic and carbonate facies, and (FA-3) non-encrinitic carbonate facies. These mid to outer ramp sediments represent deposition mostly from episodic, high-energy storm events as evidenced by hummocky cross-stratification, large wave ripples, gutter casts, and wave-enhanced sediment-gravity flow deposits. Spatial and temporal changes in siliciclastic content imply basin margin depositional environments in the eastern sections and change in climate regime from arid to humid conditions. The Chicotte deposition marks a major faunal change with the domination of crinoids triggered by increasing siliciclastic supply, rapid sea level fluctuations and change in substrates. The recognition of one major transgressive-regressive (TR) sequence subdivided in distinct meter-scale cycles allows a high resolution E-W correlation. The development of the TR sequence and meter-scale cycles is driven by glacio-eustacy where the main sequence is 4th order (~400 Ky) with superimposed meter-scale cycles that are 5th and/or 6th order (~100 Ky). Nevertheless, erosional capping surfaces within the more proximal tempestites represent ancient rocky shorelines that developed during forced sea level falls. In order to explain this stratigraphic architecture, a carbonate open-ramp model is proposed with a concave-up profile and a narrow and steep inner ramp in equilibrium with a high-energy coastline.
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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 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".