Nb AND Ta OXIDE MINERALS IN THE FONTE DEL PRETE GRANITIC PEGMATITE DIKE, ISLAND OF ELBA, ITALY
Bibliographic record
Abstract
The Fonte del Prete rare-element-enriched granitic pegmatite dike, located near the village of San Piero in Campo, Island of Elba, Italy, displays LCT-type geochemical features, and is genetically related to the Monte Capanne pluton. The dike is characterized by complex asymmetrical zoning, with miarolitic pockets containing primitive or highly evolved assemblages. There is a noteworthy presence of Nb and Ta oxides and complex oxides, occurring mainly in the pockets. Euxenite-(Y), polycrase- (Y), U–Bi-rich polycrase-(Y), and ferrocolumbite occur in the primitive pockets in the central part (core zone), whereas U–Birich polycrase-(Y), uranopolycrase, manganocolumbite, manganotantalite, “wolframo-ixiolite”, titanowodginite and microlite are found in the evolved pockets, at the extremities of the dike. Niobian rutile and euxenite-(Y) are also found in the massive pegmatite. The crystal chemistry and properties of the Nb and Ta oxides, as revealed by X-ray-diffraction studies, permit a reconstruction of the last stages of crystallization within each environment. During the evolution of the pegmatite, a volatile-rich melt with a high content of rare elements reached saturation in aqueous vapor. Minerals of Ti, Nb, Fe, Y + HREE occur in the primitive pockets; the enrichment of Mn, Ta and W in the evolved ones led to the crystallization of minerals with high Ta/(Ta + Nb) and Mn/(Mn + Fe) values, such as manganotantalite, microlite and titanowodginite. The polycrase-(Y) is unusually enriched in Bi and U, and is zoned from a Bi-poor core to a Bi-rich rim.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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 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".