Petrology and tectonic setting of the Seal Island Pluton, Southwestern Nova Scotia
Bibliographic record
Abstract
As a result of mapping and petrological study, the Seal Island Pluton is divided into two units: biotite monzogranite, which outcrops on Round, Noddy, and Mud Islands, and muscovite-biotite monzogranite, which outcrops on Seal Island. The presence of hornfelsic metasandstone xenoliths in both units suggests that the pluton intruded the Cambrian-Ordovician Meguma Group. A porphyritic tonalite dyke, pegmatite/aplite dykes, and two mafic dykes occur in the pluton. The mafic dykes occur in north-trending shear zones, and are likely syn-to late intrusive within the granite based on observed co- mingling textures. The pluton is marked by weak foliation (biotite+muscovite). Steep shear zones (<50 cm wide) are most abundant along the western side of Seal Island. Locally well developed c-s fabrics and porphyroclasts which indicate dextral strike-slip movement have developed. This deformation is likely related to the inferred offshore extension of the major Chebogue Point shear zone located west of the pluton. Relative to the biotite monzogranite, the muscovite-biotite monzogranite is higher in silica and lower in TiO₂, FeO₃ᵀ, MnO, MgO, CaO, Zr, V, and Th. These units do not show continuous chemical trends and are unlikely linked directly by fractional crystallization. Both the biotite and the muscovite-biotite units are peraluminous and have volcanic-are chemical signatures, suggesting that they formed above an offshore subduction zone. The biotite monzogranite is similar to ilmenite-bearing granite recovered in drill core west of Seal Island. The muscovite-biotite monzogranite closely resembles the Shelburne Pluton and hence the Seal Island Pluton is likely ca. 373 Ma old, like the Shelburne Pluton.
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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) | 0.004 | 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".