The origin of mafic-ultramafic bodies within the northern Dashwoods Subzone, Newfoundland Appalachians
Bibliographic record
Abstract
Mafic-ultramafic bodies of possible ophiolitic origin are widespread within the northern part of the Dashwoods Subzone of the Newfoundland Appalachians. The bodies fall into two types; the first consists of relatively undeformed, fresh, layered gabbroic bodies, which contrasts with the second that consists of metamorphosed ultramafic lithologies. Two of the largest gabbroic bodies yielded U-Pb zircon ages of 432.4±1.0 and 429.9±1.2 Ma. Their Silurian age refutes an ophiolitic origin, and, along with their hydrous nature and fresh character, indicates that they formed in the widespread Early Silurian igneous event that affected both the Dashwoods and Notre Dame subzones. Our new data further substantiate the bimodal character of the Silurian event. The ultramafic bodies are inferred to be of ophiolitic origin. Those that occur in the Dashwoods subzone are interpreted to be related to the Lushs Bight oceanic tract, whereas those in the Lloyds River Fault Zone are correlated with the Annieopsquotch ophiolite belt. RÉSUMÉ Des masses mafiques-ultramafiques d’origine possiblement ophiolitique sont répandues à l’intérieur de la partie septentrionale de la sous-zone de Dashwoods des Appalaches à Terre-Neuve. Les masses s’insèrent dans deux catégories: la première est constituée de masses gabbroïques stratifiées, récentes, relativement peu déformées, qui tranchent avec la seconde, constituée de lithologies ultramafiques métamorphisées. Deux des masses gabbroïques les plus vastes ont affiché des âges de 432,4 ±1,0 et de 429,9 ±1,2 Ma par datation U-Pb sur zircon. Leur âge silurien réfute une origine ophiolitique et, de pair avec leur nature aqueuse et leur caractère récent, signale qu’elles se sont formées au cours du processus igné étendu du Silurien précoce ayant affecté les sous-zones de Dashwoods et de Notre Dame. Nos nouvelles données attestent davantage le caractère bimodal de l’événement silurien. On suppose que les masses ultramafiques sont d’origine ophiolitique. Les masses présentes dans la sous-zone de Dashwoods sont interprétées comme des unités apparentées à la parcelle océanique de Lushs Bight tandis que celles se trouvant dans la zone de la faille de la rivière Lloyds ont été corrélées avec la ceinture ophiolitique d’Annieopsquotch. [Traduit par la rédaction]
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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".