An Early Devonian fossil assemblage in the Clam Bank Formation (western Newfoundland): implications for Lochkovian paleogeography, paleoceanography, and biogeography in the Canadian Appalachian orogen
Bibliographic record
Abstract
The Clam Bank Formation records renewed middle Paleozoic, post-Salinic, foreland-basin sedimentation in the northern Canadian Appalachian orogen, but its age has been poorly constrained. The echinoderm lobolith Camarocrinus formed the basis of a long-standing late Silurian (Přídolí) age even though the macrofossil assemblage has received little attention. Previous age assessments, including an early Lochkovian interpretation based on palynomorphs, suffered from contemporary uncertainty of, or subsequent changes to, biostratigraphic zonation. Updated taxonomy and regional stratigraphy, along with addition of new fossil material, demonstrate early Lochkovian macro- and microfossil assemblages, including the species of Camarocrinus. This enables revision of middle Paleozoic paleoenvironmental frameworks within the Canadian Appalachian orogen. In the latest Přídolí, the lowermost Clam Bank Formation was part of a platform-interior coastal plain behind a rimmed shelf (now in the Gaspé Belt) in the northern Quebec Embayment. Early Lochkovian transgression established a mixed siliciclastic–carbonate seaway in the platform interior coeval with shelf-margin drowning. This history coincides with Gedinnian transgression in northern Europe but regression within the nearby Arisaig basin (Nova Scotia), the contrast illustrating local tectonic control on base level. A diverse but poorly preserved Clam Bank macrofaunal assemblage occupied a high-energy, temperate, terrigenous-dominated nearshore setting. Faunal constituents reflect mixing of Eastern Americas and Old World fauna, Silurian holdovers, and appearance of taxa earlier than elsewhere in North America. Megaplant fossils, palynomorphs, and arthropod trackways identify a wet and dry coastal terrestrial habitat. Middle Lochkovian regression appears to have terminated the marine basin.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.003 |
| 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) | 0.002 | 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".