THE PARAGENESIS OF PYROPHANITE FROM SIERRA DE COMECHINGONES, CORDOBA, ARGENTINA
Bibliographic record
Abstract
Pyrophanite (MnTiO3) has been discovered for the first time in Argentina, associated with metamorphosed Fe ore in the Sierra de Comechingones, Province of Cordoba. The Fe ore mainly consists of magnetite, and contains large grains of Ti-rich magnetite, showing a complex unmixing assemblage composed of pyrophanite, manganoan ilmenite, an aluminous spinel, and hematite. The gangue minerals associated with the oxides are, in order of decreasing abundance, clinopyroxene, garnet, titanite, amphibole, clintonite, calcite, chlorite, quartz and rare epidote. Electron-microprobe analyses show extensive solid-solution among the end-members pyrophanite, ilmenite, and geikielite (MgTiO3). The unmixed assemblage may have been derived from oxidation of a former Mn–Mg-rich magnetite–ulvospinel solid solution, under metamorphic conditions. The lack of Mn in the silicate gangue associated with the Fe ore excludes the possible influence of Mn-rich fluids during metamorphism, and suggests that Mn was an important constituent of the original oxide protolith. Geothermometry applied to the chlorite associated with the oxides yielded temperatures as low as 300–350°C, possibly consistent with the closure of the metamorphic system. However, textural and mineralogical evidence suggest that the temperature of metamorphism was much higher, and possibly reached a stage of partial melting.
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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 | 0.000 |
| Science and technology studies | 0.001 | 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".