A tale of both sides of Iapetus – upper Darriwilian (Ordovician) graptolite faunal dynamics on the edges of two continents
Bibliographic record
Abstract
Ordovician graptolite faunal compositions between the Laurentia and Baltica margins of the Iapetus Ocean differ considerably in the upper Darriwilian (Da 3 – Da 4; upper Middle Ordovician). Detailed investigation of a number of sections in the Table Head and Goose Tickle groups in western Newfoundland and the Elnes Formation of Norway provides important new faunal data for the interval from the Holmograptus lentus Biozone to the Dicellograptus vagus Biozone. The Nicholsonograptus fasciculatus and Pterograptus elegans biozones are introduced for the Table Head and Goose Tickle groups and can be recognized widely in North America. The characteristic, but poorly correlatable, shallow-water endemic faunas of the platform regions (Atlantic and Pacific faunal realms) grade into the cosmopolitan oceanic graptolite faunas (isograptid biofacies) and provide a means to precisely correlate cold-water and warm-water endemic graptolite faunas through transitional zones. The faunal differences between western Newfoundland and Scandinavia are less pronounced than hitherto assumed, and many faunal elements can now be recognized in both regions, allowing for a more precise biostratigraphic correlation. The paleobiogeographic differentiation of both regions has been based on few, but usually extremely common faunal elements, masking the presence of important biostratigraphic marker species.
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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 | 0.001 |
| Science and technology studies | 0.000 | 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) | 0.007 | 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".