PLATINUM-GROUP MINERALS IN CHROMITITE XENOLITHS FROM THE ONVERWACHT AND TWEEFONTEIN ULTRAMAFIC PIPES, EASTERN BUSHVELD COMPLEX, SOUTH AFRICA
Bibliographic record
Abstract
Les pipes ultramafiques de Onverwacht et Tweefontein, dans la partie orientale du complexe de Bushveld, en Afrique du Sud, contiennent de petits xenolithes de chromitite qui auraient ete derives des niveaux de chromitite LG6 et MG4, et detaches lors de la mise en place des pipes. Les mineraux du groupe du platine (MGP) de ces xenolithes definissent des associations a phases multiples: a) laurite avec sulfures meconnus contenant Ir-Ni-Fe et sulfures de metaux de base, presqu'exclusivement dans la chromite saine (assemblage de type 1), b) alliages abondants (isoferroplatine, ruthenium) et arseniures a Rh-Pd-Ru (cherepanovite, ruthenarsenite, rhodarsenide, et palladodymite ou palladoarsenide, polymorphes de Pd 2 As), avec laurite et antimoniures de Pd (stibiopalladanite ou sudburyite) inclus soit dans la chromite saine, soit dans l'olivine interstitielle (assemblage de type 2), et c) sperrylite et hollingworthite en grains relativement grossiers, avec laurite accessoire, liees aux parties alterees de la chromitite hote (assemblage de type 3). Seuls les assemblages de type 1 ressemblent aux mineraux du groupe du platine typiques des echantillons de chromitite LG6 et MG4 in situ, dans lesquels laurite et cooperite (phase mineure) sont predominants. Par l'absence relative des sulfures et l'abondance des alliages et des phases arseniees, les assemblages de type 2 et 3 ressemblent davantage aux associations de MGP decrites dans la dunite mineralisee de pipes platiniferes et les niveaux metasomatises de chromitite pres du contact avec les pipes. Ces assemblages a faible teneur en soufre auraient ete formes par reaction metasomatique de la chromitite avec une composante enrichie en phase volatile issue des pipes sur un intervalle de temperatures, durant et apres la mise en place des pipes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".