Bibliographic record
Abstract
Platinum group minerals (PGM) occur either as PGM dominant deposits or as by products of Ni Cu deposits. The PGM dominant deposits are associated with mafic ultramafic layered complexes, ophiolite complexes, and Alaskan type complexes. The Ni Cu deposits containing PGM are associated with noritic rocks, intrusive equivalent of flood basalts, and komatiitic lavas and intrusions. The PGM associated with the mafic ultramafic layered complexes are dominated by Pt Pd sulfides, Pt Fe alloys, Ru sulfides (mainly laurite, occurring as inclusions in chromite), Rh sulfides, Pt Pd tellurides, Pt arsenides (mainly sperrylite) and Pd alloys. Three principal categories of mode of occurrence of PGM are evident: (1) association with base metal sulfides; (2) association with silicates; (3) association with chromite or other oxides. The PGM associated with ophiolite complexes consist predominantly of just three of the PGE: Ru, Ir and Os. Pt, Pd and Rh enter only in minor amounts or very rarely from discrete minerals. The PGM are mainly restricted to the four groups: (1) alloys (Os Ru Ir, Os Ir, Ir Os, Pt Pd Fe, Pd Sb Pt, Pt); (2) sulfides (RuS 2, OsS 2, Ir Cu sulfides); (3) sulfarsenides (OsAsS, IrAsS, PtAsS, RhAsS); (4) arsenides (PtAs 2). The PGM in the Alaskan type complexes occur primarily as Pt Fe( Ni Cu) alloys, geversite, cooperite, sperrylite, erlichmanite, and malanite Paragenetically, the PGM in the Alaskan type complexes can be subdivided into two groups. Group 1 consists predominantly of platinum bearing alloys associated with chromite and silicates segregated from high temperature silicate melts and coprecipitated with chromite, and Group 2 includes other PGM associated with base metal sulfides and arsenides formed during later metamorphism and serpentinization. The PGM from Ni Cu deposits are dominated by Pd and Pt minerals. PGM are found associated with chromitites in the layered mafic ultramafic complexes, ophiolites and Alaskan type complexes. Laurite is the dominant PGM inclusion in chromites; Pt , Pd , and Rh bearing minerals occur, in general, as interstitial phases. Many investigations agree that laurite inclusions in unfractured chromites are magmatic in origin as opposed to an earlier view that ascribed the formation of laurite to exsolution of PGE from the host chromite during cooling. Hydrothermal PGM deposits have been recognized in a variety of environments, even in the mafic ultramafic complexes. Current models for the genesis of these deposits involve transport of PGE and associated metals by chloride complexes during late stage magmatic hydrothermal processes.
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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 | 0.001 |
| 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) | 0.011 | 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".