NEW CONSTRAINTS ON THE TIMING OF MOLYBDENITE MINERALIZATION IN THE DEVONIAN ACKLEY GRANITE SUITE, SOUTHEASTERN NEWFOUNDLAND: PRELIMINARY RESULTS OF Re-Os GEOCHRONOLOGY
Bibliographic record
Abstract
New Re–Os molybdenite ages are presented from three prospects (Motu, Ackley City and Wylie Hill) located along the southern margin of the Ackley Granite suite, southeastern Newfoundland. These dates provide new constraints on the timing of high-level granite emplacement and contemporaneous granophile mineralization, and also provide a comparison with previous estimates for the age of the granite and associated mineral deposition. The ages indicate a single episode of spatially related, late-stage, syngenetic mineralization at Motu (378.1 ± 1.7 Ma, n = 1), Ackley City (379.7 ± 1.7 Ma, n = 5) and Wylie Hill (380.2 ± 1.6 Ma, n = 2). The results suggest that all three prospects formed synchronously at 379.6 ± 1.7 Ma (weighted average, n = 8). The Re–Os dates are similar to, but slightly older than previous Ar–Ar magmatic and hydrothermal mica (biotite/muscovite) ages. The preliminary Re–Os dates yield a precise timing for roof-zone crystallization and syngenetic mineral deposition in the Ackley Granite suite and also support temporal correlation of the Ackley Granite with other Late Devonian (Frasnian) granitoid plutons such as the Francois and St. Lawrence granites. The presented Re–Os molybdenite geochronology has great potential in constraining the precise timing of late magmatism and associated mineralization in Newfoundland, and facilitating correlations with analogous regions in Europe and North America.
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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 | 0.001 | 0.000 |
| 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".