The relationship between the Ganderian Aspy and Bras d'Or terranes explored using Devonian plutonic rocks, Cape Breton, Nova Scotia
Bibliographic record
Abstract
On Cape Breton Island, Nova Scotia, the Eastern Highlands Shear Zone bisects the Ganderia composite terrane, separating the Aspy and Bras D'Or terranes. The shear zone displays east-over-west, sinistral kinematics, and is intruded and stitched by plutonic rocks of the Devonian Black Brook Granite Suite. This study is utilizing whole rock geo-chemistry, U-Pb zircon geochronology and Hf isotopic analysis to constrain the petrogenesis of the Black Brook Granite Suite and other spatially associated granitoid plutons in northern Cape Breton. The granitoid-dominated plutonic suite is peraluminous, muscovite- and biotite-bearing, and interpreted to have formed from crustal anatexis. Published U-Pb monazite ages have constrained emplacement of the granite suite to ca. 375 Ma. Our new zircon geochronological data yielded weighted-mean U-Pb ages between ca. 396 and 399 Ma, but individual zircon grains recorded younger ages in all samples. Our interpretation is that many of the analyzed zircon grains are inherited from host rocks and/or protolith, or that the pressure-temperature conditions of the magma were only hot enough to grow long, slender zircon crystals not analyzed in this study. Thus, we interpret the timing of granitoid emplacement to be ca. 375 Ma. These results situate post-collisional plutonic rocks in northern Cape Breton Island in the temporal history of the Appalachian Orogen and can be used to constrain timing of deformation on the Eastern Highlands Shear 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 | 0.001 |
| 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) | 0.001 | 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".