Platinum-bearing placers of Siberian platform: mineral associations and their age characteristics as indicators of large igneous provinces manifested in old platform
Bibliographic record
Abstract
The Siberian platform is known for numerous placers of platinum-group minerals (PGM), covering vast areas in river basins of Vilyui, Lena, Aldan, Anabar, and Olenek.However, bedrock sources for the deposits are still unknown.These placers have different mineralogical-geochemical characteristics, which is due to their varying PGM associations and specific typochemical features of the minerals.It is obvious that these Pt placers of large areal extent are associated with different productive platiniferous primary rocks forming within large igneous provinces (LIPs) of mafic-ultramafic formations.In an attempt to determine likely parent rocks for the placers we compared their mineralogical-geochemical compositions with those of basic-ultrabasic rock complexes.Correlation was also made between the Re-Os and 190 Pt-4 He ages of minerals of the Ir-Os-Ru composition, ferroan platinum, isoferroplatinum, and sperrylite from the placers and times of major magmatic events that occurred in the Siberian platform.The results obtained suggest that the sources for the studied Pt placers might be buried mafic-ultramafic rocks which are manifestations of major Precambrian magmatic events occurred 1900, 1865, 1750, 1700, 1640, 1500, 1350, 1258, 725 million years ago.The Phanerozoic productive Pt deposits were formed in relation to Riphean and Middle Paleozoic rift, a Paleozoic-Mesozoic episode of the manifestation of the Siberian mantle plume in the form of giant eruptions of basic and alkali-ultrabasic magmatic rocks as well as active Mesozoic tectonomagmatic transformations in the southern margin of the Siberian platform.
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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 | 0.000 | 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) | 0.001 | 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".