Chlorine-Enriched Tourmalines In Hydrothermally Altered Diorite Porphyry From the Biely Vrch Porphyry Gold Deposit (Slovakia)
Bibliographic record
Abstract
Chlorine-enriched tourmaline was found in a hydrothermally altered Miocene diorite porphyry at the Biely Vrch porphyry gold deposit (Central Slovakia) as a relatively rare alteration mineral forming radial aggregates composed of thin prismatic crystals in the central part of quartz veinlets filled by calcite. Zoned tourmaline with Cl-enriched central zones is accompanied by allanite-(Ce) to epidote, fluorapatite, Al-rich titanite, magnetite, rutile, ilmenite, and pyrite. The tourmaline chemical composition is controlled by exchange of Fe 2+ for Al at relatively constant Mg content. It produces a trend from the earliest X -site vacant Al-rich oxy-tourmaline in the central part of tourmaline aggregates to the latest feruvite on their margins. Tourmalines belong to three groups: X -site vacant (“ vacancy-Mg-O root name” tourmaline, magnesio-foitite, and foitite), alkali (oxy-schorl, schorl), and calcic (feruvite) tourmaline. The variation in Al and Fe content is the result of concomitant action of AlOFe −1 OH) −1 , Al X □Fe −1 Na −1 , and FeCaAl −1 Na −1 substitutions. Enrichment in Ca likely results from FeCaAl −1 Na −1 substitution. The Cl content in tourmaline from Biely Vrch attains 0.45 wt.%, which is equivalent to 0.126 apfu . The chlorine content increases with decreased Fe and increased octahedral Al and X -site vacancy. Bond-length calculations yield six bond-valence and bond-length probable local structural arrangements with W Cl, and these are all characterized by dominance of Al at the Y sites and O at the V sites. Based on the analytical data and bond-length calculations, the chemical composition of Cl-enriched tourmaline is a result of crystallographic factors as well as petrologic environmental conditions. The enrichment in Cl is most likely related to the unusually Cl-rich hot hydrothermal fluid responsible for the origin of the host Biely Vrch porphyry gold deposit. The Cl incorporation in tourmaline is influenced by Fe availability in the genetic environment; increased Fe 2+ substitution for Al reduces the ability of tourmaline to incorporate Cl.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".