Accurate and precise Re-Os molybdenite dates from the Galway Granite, Ireland. Critical comment on “Disturbance of the Re-Os chronometer of molybdenites from the late-Caledonian Galway Granite, Ireland, by hydrothermal fluid circulation” by Suzuki et al., Geochemical Journal, 35, 29-35, 2001
Bibliographic record
Abstract
SAMPLES AND ANALYTICAL METHODOLOGYFor Galway Mace, the same sample used by Suzuki et al. (2001) was used here, but for Galway Murvey, a new sample was collected from the same location as the original (figure 1, location 1 and 2 of Suzuki et al., 2001).Molybdenite descriptions were not reported by Suzuki et al. (2001), and thus are given here.For Galway Mace, abundant molybdenite of 2 to 4 mm size occurs disseminated and as rosettes of ~1 cm diameter on the vein margin adjacent to alteration selvage.For Galway Murvey, minor disseminated molybdenite of 1 to 4 mm is present within the granite.A full mineral separate was obtained for each sample using conventional isolation techniques (cf., Selby et al., 2003), yielding ~2 g of molybdenite for the Galway Mace sample, and a total of 900 mg molybdenite from ~9 kg of rock for Galway Murvey.The 187 Re and 187 Os concentrations in molybdenite were determined from an aliquot (Table 1) of the mineral separate by isotope dilution mass spectrometry at the University of Alberta Radiogenic Isotope Facility using Carius tube, solvent extraction and chromatographic techniques (Selby and Creaser, 2001a).Rhenium and Os isotope ratios were measured using negative thermal ionization mass spectrometry (Creaser et al., 1991;Völkening et al., 1991) on a Micromass Sector 54 mass spectrometer using Faraday collectors.The Re-Os data for the Galway Mace and Galway Murvey molybdenite samples are presented in Table 1. RESULTSThe Re and 187 Os contents and Re-Os dates of
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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 | 0.006 | 0.032 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.007 | 0.010 |
| Insufficient payload (model declined to judge) | 0.002 | 0.003 |
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".