Nd isotopic characteristics of terranes within the Avalon Zone, southern New Brunswick
Bibliographic record
Abstract
Nd isotopic data are presented for rock units in four terranes within the traditional Avalon Zone of southern New Brunswick. Initial εNd values for igneous rocks within the Caledonia terrane range from -1.6 to +4.6, whereas values for sedimentary rocks range from -8.4 to +3.6. A granite within the Kingston terrane has εNd(438 Ma) = +4.0. Nd isotopic compositions for the Kingston and Caledonia terranes are similar to those of the Mira terrane in Cape Breton Island, the Antigonish Highlands of Nova Scotia, and plutonic rocks of eastern Newfoundland. Each of these regions may be a dismembered part of a single terrane, the Avalon terrane sensu stricto. Initial εNd values for rocks from the Brookville terrane range from -1.3 to +2.8. The Coverdale anorthosite within the Brookville terrane has a present day εNd value of -12.1 and a depleted mantle model age of 1.3 Ga, similar to Mesoproterozoic anorthosites in Laurentia. Clastic sedimentary rocks in the Green Head Group have εNd(750 Ma) values of -2.0 and -10.9. Viewed as a whole, the Brookville terrane is isotopically more evolved than the Caledonia terrane. Initial εNd values for rocks in the New River terrane range from -2.9 to 0.0. The Nd isotopic composition of the Brookville and New River terranes are thus similar to one another and have isotopic character similar to that of the Bras d'Or terrane of Cape Breton Island. It is suggested that all three regions belong to a single terrane (Bras d'Oria).
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".