Intrusion-related (ca. 422 Ma), monzogranite-hosted Au-Ag-Sb mineralization at the Yellow Fox zone, eastern Mount Peyton Intrusive Suite, north-central Newfoundland, Canada
Bibliographic record
Abstract
The northeastern and eastern parts of the ca. 425–416 Ma Mount Peyton Intrusive Suite in north-central Newfoundland, Canada, host several Au-Ag-Sb-bearing mineralized zones associated with fracture systems and narrow quartz veins mantled by wide, potassic (sericite-muscovite) alteration envelopes bearing arsenopyrite and locally pyrite and stibnite. The Yellow Fox zone is hosted in a medium-grained and plagioclase-porphyritic, granophyric-textured biotite ± hornblende I-type transitional to A2-type monzogranite in the northeastern part of the intrusive suite that is cut by rectilinearly fractured, muscovite-arsenopyrite-pyrite-rutile-alteration zones. This alteration occurs in an ~100 m long by 30 m wide, north-trending bleached and rusty alteration zone characterized by three distinct fracture sets: (1) a widely spaced, roughly east-west barren set; (2) a prominent north-trending 5–20 cm spaced set accompanied by abundant muscovite and disseminated arsenopyrite + pyrite; and (3) a weakly-developed, north-northeast-trending set that locally hosts a few narrow (<4 cm) stibnite-quartz-arsenopyrite veins with arsenopyrite mainly confined to the quartz vein margins and intensely altered to supergene scorodite and goethite. Relative to unaltered granite, both muscovite-pyrite-arsenopyrite-rutile-altered monzogranite and stibnite-quartz-arsenopyrite-veined monzogranite are anomalous in many metals (Sb <11.1 wt.%; As < 4.5 wt.%; Au <59.4 g/t; Ag < 73g/t; Pb <5.5 wt.%; Zn <7 wt.%; Cd <717 ppm). The altered host rock yielded a crystallization age of 422.3 ± 1.3 Ma (CA-ID-TIMS U–Pb zircon), overlapping in error with two 40Ar/39Ar incremental-heating ages of 422.4 ± 0.2 Ma and 422.9 ± 0.6 Ma for muscovite from the same altered monzogranite. The coincident ages indicate that monzogranite crystallization and alteration were synchronous and therefore intrusion-related and formed broadly contemporaneously with proximal, mineralogically similar, intrusion-hosted mineralization in the region. Undated Au-Ag-As-Sb mineralization in the adjacent surrounding country rocks may also have been coeval. Fracturing, release of hydrothermal + magmatic fluids from deeper seated intrusions, and mineralization occurred during the final stages of monzogranite crystallization, which is interpreted to be associated with transient lithospheric extension that preceded north- to northwest-directed oblique Acadian thrusting, folding, and proximal orogenic Au mineralization in the Early Devonian (ca. <415 Ma).
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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 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".