Hydrothermal fluid evolution at the Maisie gold occurrence, Menneval, New Brunswick
Bibliographic record
Abstract
The Maisie gold occurrence, Menneval, New Brunswick, is hosted by Middle to Late Ordovician, fine grained clastic sedimentary rocks of the Whites Brook Formation, located within the Aroostook–Percé Anticlinorium. The Maisie occurrence consists of veins containing two generations of quartz (laminated and massive), hematite, pyrite, and trace chalcopyrite and galena. Electrum has a close spatial relationship with hematitized pyrite, and is late stage infilling vugs and fractures. “Hot” cathodoluminescence imaging of vein quartz is consistent with low grade metamorphism. Stable oxygen isotope analysis of quartz by SIMS shows relatively homogeneous [delta superscript 18]O[subscript V-SMOW] values between 12.3 and 18.8‰ (Fig. 15a). Estimated initial fluid [delta superscript 18]O[subscript V-SMOW] composition was between 7.0 and 18.5‰, consistent with both sedimentary-derived metamorphic waters and magmatic fluid sources, and inconsistent with meteoric or formation water. Fluid inclusion microthermometry of rare, two phase (L+V at 20[degrees]C) secondary inclusions gave an average temperature of homogenization of 170.3 [plus or minus] 30.8[degrees]C (1σ, n = 150), and an average salinity of 2.8 ± 2.2 wt% eq. NaCl (1[sigma], n = 150). Inclusion petrography (an abundance of low density vapour inclusions with rare two phase parental fluids) and isochoric data suggests rapid decompression and boiling, a potential mechanism for gold deposition. Laser Raman spectroscopy shows that minor methane and nitrogen are present in the vapour phase. The common occurrence of electrum with hematite suggests an interaction with oxidized meteoric waters, but the stable isotope and fluid salinity data do not support this idea. Maisie is considered here to represent an epizonal-orogenic Au occurrence. Rutile found within the veins shows enrichment in tin, tungsten, and rare-earth elements, and high niobium/tantalum ratios. These characteristics do not occur in rutile found within adjacent host rocks, providing a potential indicator mineral for regional exploration.
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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 | 0.001 |
| 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 | 0.001 | 0.001 |
| 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".