Ordovician stratigraphy and faunas of the Glenogle Formation, southeastern British Columbia
Bibliographic record
Abstract
The Glenogle Formation (age: Arenig to very early Caradoc) accumulated in the White River Trough between the Purcell Platform to the west and the Bow Platform to the east. The formation is up to 851 m thick, its basal contact is conformable with the McKay Group, and the upper contact is an unconformity below Upper Ordovician rocks that elsewhere cuts down as low as into the Precambrian. The Upper Member of the Glenogle has significant contents of quartz silt and sand within successions of shale in western outcrops and within dolomite in eastern outcrops. The Lower Member is dominantly shale and limy shale but, in eastern outcrops, can be divided into four units (basal, cherty quartz siltstone, middle, and limestone units) by means of incursions of detrital carbonate and siliceous sediments that were swept into the White River Trough from the Bow Platform. Debris flows within western outcrops of the Lower Member demonstrate the presence of shallow-water carbonate rocks on the Purcell Platform during early Llanvirn time. Thermal maturities are high in the Glenogle Formation (Conodont Alteration Indices mostly 4-5; Graptolite Maximum Reflectances 7.93-11.9%). Graptolites are prominent in the Glenogle Formation and the Pendeograptus fruticosus-Tetragraptus approximatus, Didymograptus bifidus, Isograptus victoriae maximus, Oncograptus, Cardiograptus, Paraglossograptus tentaculatus, Pseudoclimacograptus decoratus, "Glyptograptus" euglyphus and Nemagraptus gracilis zones are recognized and can be correlated with precision with graptolite sequences in Australia, New Zealand, Newfoundland, and Spitsbergen. The local presence of shelly fossils and recovery of conodonts from a few stratigraphic sections allow correlations between the graptolitic facies of the Glenogle Formation and the Spitsbergen sequence and with the platform facies of the North American craton. The upper part of the Ibexian Series is correlated with the Bendigonian, Chewtonian and lower Castlemanian stages; the Orthidiella and Anomalorthis zones of the lower Whiterockian Series with the upper Castlemanian, Yapeenian and the Darriwilian stages; and the Valhallan Stage of Spitsbergen with the late Bendiognian to early Darriwilian. The Prioniodus elegans Conodont Zone of the Atlantic Faunal Realm and the Oepikodus communis and Jumudontus gananda-Reutterodus andinus zones of the Midcontinental Faunal Realm are at least partly correlative with the D. bifidus Zone. Conodonts of early Whiterockian age occur with graptolites of the I. v. maximus Zone. Conodonts representing the Histiodella altifrons Zone occur in the Cardiograptus Zone and also just above the graptolites of the Oncograptus Zone. Faunas representative of the interval Lenodus variabilis Zone to Eoplacognathus suecicus Zone are present within the P. decoratus Zone and also directly above the P. tentaculatus Zone. Faunas with Phragmodus flexuosus occur above the P. decoratus Zone and below the "G." euglyphus Zone. The Pygodus serra Zone is represented within the upper part of the "G." euglyphus Zone.
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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 | 0.003 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".