Pyroxene reflectance spectra: Minor absorption bands and effects of elemental substitutions
Bibliographic record
Abstract
Reflectance spectra of a suite of compositionally diverse pyroxenes exhibit variable spectral properties which are associated with various elemental substitutions. Those associated with transition series elements, such as Cr, Ti, V, and Mn, give rise to a number of minor absorption bands in the visible spectral region and, in some cases (e.g., Mn), at longer wavelengths. Substitutions by other cations, such as Li and Zr, do not result in distinct absorption bands. The spectra of these pyroxenes are dominated by the transition series elements that may be present in the samples. The visible wavelength region of low‐calcium pyroxene reflectance spectra exhibit a number of absorption bands which are attributable to Fe2+ spin‐forbidden crystal field transitions. Fe2+‐Fe3+ intervalence charge transfer absorption bands near 0.77 μm are common in terrestrial pyroxenes which contain both ferrous and ferric iron. Collectively, these results indicate that the presence of various transition series elements can be detected in reflectance spectra and that their oxidation states and site occupancies can also be determined on the basis of unique spectral characteristics present in their reflectance spectra, thereby greatly increasing the range of compositional information which can be derived from analysis of their reflectance spectra.
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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 | 0.000 | 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) | 0.003 | 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".