U–Pb Age of the Stanley Brook Granite, Grand Manan Island, New Brunswick
Bibliographic record
Abstract
The Stanley Brook Granite on Grand Manan Island has yielded an Early Cambrian U-Pb zircon age of 535 ± 2 Ma. The granite was emplaced into sedimentary rocks of the Flagg Cove Formation of the Castalia Group, proving that the latter is no younger than Early Cambrian. Previous dating of detrital zircons from the Flagg Cove Formation limits its maximum depositional age to be no older than 574 ± 7 Ma. The intrusive age of the Stanley Brook Granite is essentially identical to the 539 ± 3 Ma age obtained previously from dacitic tuff of the Priest Cove Formation, suggesting a comagmatic relationship between the two. The contact between the Flagg Cove and Priest Cove formations is invariably faulted. However, the consanguineous relationship between the Priest Cove Formation and Stanley Brook Granite suggests that the Priest Cove Formation was deposited on the Flagg Cove Formation. This proposed stratigraphic relationship supports the interpretation that the tuffaceous and volcaniclastic sedimentary rocks of the Priest Cove Formation represent a distal facies of the mafic flows and fragmental volcanic rocks of the Ross Island Formation. The age of the Stanley Brook Granite is consistent with the interpretation that Mesoproterozoic (?) to Neoproterozoic platformal carbonate rocks of the Brookville terrane represent basement to Neoproterozoic volcanic rocks of the New River terrane.
 
 RÉSUMÉ
 
 L’âge U-Pb sur zircon du granite du ruisseau Stanley, sur l’île Grand Manan, se situerait à environ 535 ± 2 Ma et remonterait au début du Cambrien. Ce granite a été mis en place dans les roches sédimentaires de la Formation de Flagg Cove du groupe de Castalia, ce qui établirait que cette dernière formation date tout au plus du début du Cam-brien. Les travaux de datation précédents des zircons détritiques de la Formation de Flagg Cove ont fixé l’âge maximal de la sédimentation à 574 ± 7 Ma, tout au plus. Pour l’essentiel, l’âge de l’intrusion du granite du ruisseau Stanley correspond à l’âge de 539 ± 3 Ma déjà déterminé pour le tuf dacitique de la Formation de Priest Cove, ce qui donnerait à penser qu’il y a une relation comagmatique entre les deux. La zone de contact entre les formations de Flagg Cove et de Priest Cove est pratiquement toujours faillée. Toutefois, l’origine commune de la Formation de Priest Cove et du granite du ruisseau Stanley porte à croire que la sédimentation de la Formation de Priest Cove s’est superposée à la Formation de Flagg Cove. Ce lien au plan stratigraphique viendrait corroborer l’interprétation voulant que les roches sédimentaires tufacées et volcanoclastiques de la Formation de Priest Cove sont de fait un faciès éloigné des coulées mafiques et des roches volcanoclastiques de la Formation de Ross Island. L’âge établi pour le granite du ruisseau Stanley va dans le sens de l’interprétation voulant que les roches carbonatées dans la succession de plateformes du Mésoprotérozoïque (?) au Néoprotérozoïque du terrane de Brookville forment le socle des roches volcaniques du Néoprotérozoïque du terrane de New River. [Traduit par la redaction]
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.017 | 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 teacher head, 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".