Subsurface Correlation of Lower Silurian Medina Group, Southwestern Ontario
Bibliographic record
Abstract
The Medina Group succession in southwestern Ontario includes, in ascending order: the Whirlpool, Manitoulin, Cabot Head, Power Glen, Devils Hole-Balls Falls, Grimsby, and Thorold formations. Subsurface mapping in central and eastern Lake Erie has resulted in the recognition of three stratigraphic packages within the Medina Group based upon the integration of sedimentologic, stratigraphic and geophysical borehole logs. The interplay between changing paleoenvironments, sediment provenance, and regional tectonics and associated sea level fluctuations has resulted in the accumulation of a complex mosaic of mixed siliciclastics and carbonates. Manitoulin Formation carbonates and Whirlpool Formation siliciclastics display consistent thicknesses across the study area. Sitting disconformably above these strata are the Cabot Head/Power Glen grey/green shales with thin quartz sandstone stringers. This shale-dominated succession is overlain by the Devils Hole Formation pink/grey, slightly dolomitic medium to fine grade quartz sandstones and the Ball’s Falls dolostones and mixed dolomitic shales. A subregional phosphatic nodule horizon, recognized in the Niagara Region as the Artpark phosphate bed, has been correlated across the study area. The overlying Grimsby Formation is characterized by interbedded red and green sandstones, siltstones, and shales, with multiple bryozoan biostromes in the western part of the study area. The greenish-grey quartz arenites of the Thorold Formation cap the Medina Group succession and with the underlying Grimsby Formation represent a historically significant gas play in southwestern Ontario.
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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 | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".