Upper Ordovician conodont biostratigraphy and the age of the Collingwood Member, southern Ontario, Canada<sup>1</sup>Earth Science Sector (ESS) Contribution 20100302.
Bibliographic record
Abstract
The Upper Ordovician stratigraphy in southern Ontario represents the clastic foredeep associated with the Appalachian Taconic Orogeny transitioning northwest into coeval carbonate platform facies. Ten measured and sampled sections in both the Collingwood area and on Manitoulin Island, Lake Huron, provide two relatively complete composite sections (277 and 95 m, respectively) through the marine part of the sequence. A total of 100 2 kg samples collected for a conodont biostratigraphic study yielded 77 215 well-preserved specimens. Taxonomic study of the fauna, illustrated herein, identified 34 species representing 22 genera and three taxa in open nomenclature. Taxonomic revisions are made to five species of Pseudobelodina and one of Rhipidognathus ; a new species, Pseudobelodina microdentata , is established. The fauna primarily represents the Midcontinent Province with incursions from the North Atlantic Province primarily in the Collingwood area. Four conodont zones are recognized that help refine the ages for the Upper Ordovician upper Lindsay (Collingwood Member), Blue Mountain, Georgian Bay, and Queenston formations. In particular, the Collingwood Member of the Lindsay Formation, a regionally distributed organic-rich shale of hydrocarbon source rock potential, is demonstrated to lie within the Amorphognathus ordovicicus Zone of North Atlantic Province and the Oulodus robustus Zone of Midcontinent Province and to be early Richmondian age.
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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 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.016 | 0.002 |
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".