Conodont biostratigraphy of the latest Cambrian - Early Ordovician upper McKay Group, southeastern British Columbia
Bibliographic record
Abstract
The age of the upper McKay Group based on conodont biostratigraphy is latest Cambrian (Cordylodus proavus Zone) to late Early Ordovician (middle Floian; Oepikodus communis Zone). A collection of 12 940 conodont elements was recovered from 306 samples of upper McKay Group strata exposed in the Western Main Ranges of the southern Canadian Rocky Mountains, southeastern British Columbia. The conodont fauna is assigned to 53 species representing 30 genera. Twelve zones are recognized, two of which are cosmopolitan: Cordylodus proavus Zone and Iapetognathus Zone. Seven Midcontinent Realm zones, in ascending order, include Polycostatus falsioneotensis, Rossodus tenuis, Rossodus manitouensis, low diversity interval, Scolopodus subrex, and Acodus kechikaensis zones, and Tropodus sweeti Subzone (of the Oepikodus communis Zone). Three Atlantic Realm zones, in ascending order, include Cordylodus angulatus, Acodus deltatus, and Paroistodus proteus zones. The zonation for the upper McKay Group establishes correlation with the Survey Peak Formation and lower Outram Formation of the Bow Platform, and with the Kechika Formation and lower Skoki Formation of the Macdonald Platform and Kechika Trough in the northern Rocky Mountains. The McKay Group represents deposition during post-rift thermal subsidence of the margin, although its thickness, abrupt transition to black shale of the overlying Glenogle Formation, and intercalation of volcanogenic rocks imply a history of differential subsidence similar to that of the northern Cordillera, probably related to periodic extension.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".