Abstract: The Lower Devonian North Pole Stream Pluton: A strongly peraluminous granitic complex hosting a polymetallic vein-type uranium deposit, New Brunswick, Canada
Bibliographic record
Abstract
The North Pole Stream Pluton (NPSP) underlies an area of about 500 km2 between Trousers Lake and Big Bald Mountain in north-central New Brunswick. Magmatic fractionation produced four, probable, comagmatic differentiates namely: biotite granite (oldest phase); biotite-muscovite granite; muscovite granite; and quartz-feldspar porphyry (QFP) granite that crosscuts all other phases of the pluton. Existing petrochemical data for the NPSP suggest that the muscovite granite is the most highly evolved phase in that it has A/CNK = 1.3–1.4, a P/Ca higher than apatite, has low ∑REE (8.4 ppm), Zr/Hf (16.8), Nb/Ta (5.9), and Th/U (0.04), and is enriched in Rb (542.3 ppm), Sn (30.7 ppm), Nb (51.8 ppm), Ta (8.8 ppm), and U (28.5 ppm). The fractional crystallization of monazite, xenotime, zircon, and apatite in the muscovite granite produced extreme depletions in HFSE’s and the REE’s, and chondrite-normalized REE patterns with low LREEs/HREEs and a slight discontinuity between Nd and Sm. Other phases of the pluton are far less fractionated and represent a continuous differentiation series that becomes increasingly more perphosphorus and uranium-specialized with decreasing age. The excess P is located primarily in K-feldspar, is enriched in the rims compared to the core of the grains, and increases in concentration with decreasing age of the hostgranitoid. Ba and Cs have a similar relationship in K-feldspar; however, their concentrations decrease with increasing degree of fractionation. A number of radiometric ages have been reported from the NPSP. A sample of biotite granite obtained from approximately one half kilometre south of the study area has yielded a U-Pb monazite age of 417 ± 1 Ma, and has been interpreted as the emplacement age of the NPSP. A ten-point whole-rock isochron from the biotite to the east of the map area gave an age of 387 ± 7 Ma with an initial 87Sr/86Sr ratio of 0.703. A muscovite K-Ar age of 414 ± 5 Ma and a Rb-Sr age of 381±4 Ma have been reported from one sample of muscovite granite and, from another sample, Rb-Sr ages of 425 ± 4 Ma and 397 ± 4 Ma have been obtained from muscovite and biotite respectively. Recent CHIME dating of quartz-hosted monazite inclusions in the muscovite granite has yielded an age date of 421 ± 6 Ma, implying the monazite inclusions pre-date the muscovite granite and are inherited from an earlier phase in the crystallization history.
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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 | 0.002 | 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) | 0.010 | 0.001 |
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".