THE ARSHAN REE CARBONATITES, SOUTHWESTERN TRANSBAIKALIA, RUSSIA: MINERALOGY, PARAGENESIS AND EVOLUTION
Bibliographic record
Abstract
The Arshan carbonatites in the Transbaikalia region of Siberia consist of sovite with high concentrations of the REE, Sr, Ba, and SO 3 , and low concentrations of Nb and P 2 O 5 . There was a high fugacity of oxygen and fluid activity at the time of formation of these carbonatites, and they were later altered by hydrothermal solutions. Bastnasite formed as a magmatic mineral in the carbonatites, on the basis of petrographic evidence and fluid-inclusion data. The recrystallization of calcite, the replacement of bastnasite and phlogopite, and the formation of secondary sulfates, strontianite, calcite and fluorite resulted from a hydrothermal process. The 87 Sr/ 86 Sr values of minerals in the Arshan carbonatites are higher than in many other carbonatites, but are similar to those in the continental basalts of Transbaikalia. The δ 34 S CDT values resemble those of other Transbaikalia carbonatites and alkaline rocks. The δ 13 C V–PDB isotopic values in the carbonatite plot within the field defined for primary igneous carbonatites. On the other hand, δ 18 O V–SMOW values for the Arshan bastnasite is only partially within the usual range of mantle values. The altered carbonatites are characterized by lighter δ 18 O values, probably because of the influence of meteoric water. The carbonatites were formed from an enriched source in the mantle and crystallized rapidly at shallow depth.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".