Oscillatory zoned liddicoatite from Anjanabonoina, central Madagascar. II. Compositional variation and mechanisms of substitution
Bibliographic record
Abstract
The compositional variation from core to edge of a (001) section of liddicoatite (diameter~20 cm) from the Anjanabonoina granitic pegmatite in Madagascar shows pronounced oscillatory zones. Over the bulk crystal, the compositional variation corresponds to the two substitutions, X Na + Y M * → X Ca + Y Li and Y M * + Y M * → Y Li + Y Al ( M * = Fe + Mg + Mn), and the oscillatory zoning is superimposed on a smooth monotonic variation in the principal constituents. Both Fe and Mg show prominent oscillatory behavior superimposed on background values of~0 apfu , and Mn and (Mg + Fe) show antithetic behavior with regard to compositional variation. The pattern of compositional zoning is completely different in the {021} and {110} sectors of the crystal. In the pyramidal sector, individual zones range in width from apfu from the center to approximately halfway toward the edge of the crystal, and remains close to zero out to the edge. Four colors of zones are observed: purple, light green, dark green, and greenish black, owing to an overall decrease and increase in Mn and Fe contents, respectively. In the pyramidal sector, each zone starts with a sharp increase in Fe and Mg, which then monotonically decrease to zero across the zone, and this pattern is repeated across the series of zones. In the prism sector, Fe and Mg are zero at the beginning of each zone and gradually increase to reach maximum values at the end of each zone, followed by a sharp drop to~0 apfu . The complexity of the compositional behavior reported here requires future development of a more complex model for the zoning process of liddicoatite at Anjanabonoina.
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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 | 0.001 | 0.001 |
| 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".