Sedimentology and sequence stratigraphy of the Ordovician Black River and lower Trenton Groups, Lake Simcoe area, Ontario
Bibliographic record
Abstract
The Black River and Trenton Limestone Groups of southern Ontario are a relatively thin (average 150 metres) carbonate succession in the Lake Simcoe area, resting unconformably on Precambrian basement. Local Precambrian 'highs' complicate the overall facies pattern and lithofacies patterns define local shoal, intershoal and basinal environments. Detailed microfacies and facies analysis in large quarries in the Lake Simcoe area are used to infer various carbonate environments by comparison with analogous modern and ancient ramps. Fifteen microfacies are grouped into six microfacies associations based on composition, grain size and texture. Relative energy levels, and depositional environments for these are then inferred. These environments resemble the Recent Arabian Shelf of the Persian Gulf for the Black River Group, and the Recent West Florida Shelf for the Trenton, though other Recent ramps like South Australia are also comparable. The vertical arrangement of facies in the Lake Simcoe area form repetitive cycles which can then be traced laterally into adjacent areas, complicated by the effects of sea-floor topography and possibly by synsedimentary faulting. Both minor and major cycles are dominantly coarsening upwards, and normally bounded by sharp non-depositional surfaces representing marine transgressions. Both minor and major cycles are compared to those of other ancient successions, and those inferred from cores in the modern ramps used for the microfacies and facies comparison. Their development can be related to both autocylic and allocyclic processes. The facies architecture of the cycles across southern Ontario show that they are the basic architectural elements of the Black River-Trenton transgressive systems tract. The major cycles form five backstepping parasequences extending across southern Ontario from Manitoulin Island to Kingston. Periodic uplift and subsidence of the area, fluctuation in the position of the relative sea level, local tectonism, and sea-water temperatures were responsible for development of the succession.
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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 | 0.002 | 0.002 |
| 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) | 0.004 | 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".