The crystal-chemistry of non-metamict pyrochlore-group minerals from Latium (Italy). The Canadian Mineralogist
Bibliographic record
Abstract
We here present reults of a crystal-chemical study of a suite of pyrochlore-group minerals from the holocrystalline syenitic ejecta scattered within the Plio-Pleistocene pyroclastic deposits of Latium, in central Italy. Despite their high actinide content, the samples studied are non-metamict owing to their young age of formation, as suggested by the well-defi ned and sharp peaks in the X-ray powder-diffraction patterns. The measured a unit-cell dimension is correlated with the (Ti + Fe3+) content at the B site of the structure. Following the IMA classifi cation scheme for pyrochlore-group minerals modifi ed according to the “50% rule ” adopted in 1992, the samples are classifi ed as betafi te, pyrochlore and uranpyrochlore. In comparison with known data for pyrochlore-group minerals, the samples have extremely high Ti contents (up to 81.3 atom % Ti relative to the Ti + Nb + Ta sum) and signifi cant and variable contents of Zr (up to 8.44 wt. % ZrO2) and W (up to 12.14 wt. % WO3). Some crystals display strong compositional zoning, consistent with the substitution 3Nb5+ + Na+ 3Ti4+ + U4+. The accommodation of extremely high amounts of W6+ can be related to the coupled substitution 2(Nb + Ta)5+ Ti4+ + W6+ at the B site. Pyrochlore-group minerals from Latium have signifi cantly high REE contents (up to 7.75 wt. % oxide). Chondrite-normalized patterns follow the general
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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) | 0.001 | 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 teacher head, 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".