Origin of Platinum-Group Mineral Assemblages from Placers in Rivers Draining from the Ural-Alaskan Type Itchayvayamsky Ultramafics, Far East Russia
Bibliographic record
Abstract
The Itchayvayamsky Ural-Alaskan-type massif is located in the northernmost part of the Koryak-Kamchatka Platinum Belt (Russia) and is surrounded by two rivers (Kamenistaya and Itchayvayam) that both contain specific PGM (platinum group minerals) assemblages. The PGMs of the Kamenistaya River are represented by isoferroplatinum with minor admixtures of Pd and Cu (up to 1.97 and 1.37 wt.%, respectively) and numerous inclusions of other PGMs such as laurite, erlichmanite, and boweite. The Itchayvayam River assemblage is different, as it contains minor amounts of isoferroplatinum and other minerals identical to those of the Kamenistaya River, as well as abundant native platinum rich in Cu and Pd (up to 4.30 and 2.34 wt.%, respectively) and rimmed by secondary cooperite and malanite. Grains of gold intergrown with unnamed Au-Hg-Pd minerals, cooperite, vysotskite, and malanite were also found exclusively in the Itchayvayam River. Three mineral assemblages are spatially related to the Itchayvayam massif and are distinguished by: (1) isoferroplatinum, (2) native platinum, and (3) gold-mercury-palladium. Isoferroplatinum assemblages are typical for placers derived from Ural-Alaskan-type massifs and lodes (e.g., the Galmoenan massif in the Koryak Highlands). Simultaneously, the native platinum assemblages are rare and have been described as lodes in clinopyroxenites, and in sub-economic placers derived from clinopyroxenite-dominant massifs. Therefore, it is assumed that the origin of the first assemblage is from lodes in dunite and the second is from lodes in clinopyroxenite. In addition, gold-mercury-palladium assemblages apparently originated from mineralized zones, analogous to those intruding gabbro and monzonite at the nearby Barany massif, which contains native gold and Pd-sulfides. Our study of the structure and compositions of Pt-Fe minerals showed that in the structure of isoferroplatinum Cu and Ni substitute for Fe, whereas in native platinum they substitute for both Pt and Fe.
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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 | 0.000 |
| 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) | 0.002 | 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 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".