Minor elements in pyrites from the smithers map area, b.c. and exploration applications of minor element studies
Bibliographic record
Abstract
This study was undertaken to determine minor element geochemistry of pyrite and the applicability of pyrite minor-element research to exploration for mineral deposits. Previous studies show that Co, Ni, and Cu are the most prevalent cations substituting for Fe in the pyrite lattice; significant amounts of As and Se can substitute for S. Other elements substitute less commonly and in smaller amounts within the lattice, in interstitial sites, or within discrete mechanically-admixed phases. Mode of substitution is determined most effectively with the electron microprobe. Cation substitution for Fe²⁺ is favored by transition elements with non-bonding "d" electrons .in low-spin configurations, an octahedral covalent radius similar to that of Fe (1.23 [symbol omitted] and high electronegativity. Anion substitution for S is favored by chalcogeri and pnigogen elements with a tetrahedral coordination radius close to 1.04 [symbol omitted] and high electronegativity. Statistical tests performed on several hundred pyrite analyses compiled from the literature and stored on computer cards support: (l) log-normal frequency distributions of minor elements in hydrothermal pyrite; (2) redistribution of minor elements in pyrite by metamorphism; (3) statistical differentiation of hydro-thermal, volcanic-exhalative, and syngenetic pyrites on the basis of Co and Ni concentrations and ratios; (4) relationship of minor element "spectra" and concentrations in disseminated pyrite to those in adjacent rocks; and (5) relationship of minor-element concentrations in hydrothermal pyrites to major ore-forming elements present. Forty pyrite samples from several distinct types of mineral deposits in the Smithers area, B.C. were analyzed for Co, Ni, Mn, Cu, Pb, and Zn using atomic-absorption spectrophotometry. Co concentrations are highest in pyrites from volcanic rocks, massive sulphide deposits and a breccia pipe. Ni and Mn concentrations are uniformly low. High contents of Cu, Fb, and Zn are caused by inclusions of common sulphides. Calculation of correlation coefficients for minor elements revealed that contamination does not significantly affect Co or Ni concentrations. Minor element data from the Smithers pyrites provides evidence for genetic relationships between several different mineral deposits, the presence of "metallogenetic" sub-provinces, and minor-element zonation in mineral deposits. Research into minor-element geochemistry of pyrite can be useful in exploration for mineral deposits; most effective use is during secondary stages of exploration. Most useful elements for exploration applications are Co, Ni, Cu, Au, Ag, Hg, Tl, Sn, As, and Se.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 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".