POLLUCITE AND THE CESIUM-DOMINANT ANALOGUE OF POLYLITHIONITE AS EXPRESSIONS OF EXTREME Cs ENRICHMENT IN THE YICHUN TOPAZ LEPIDOLITE GRANITE, SOUTHERN CHINA
Bibliographic record
Abstract
The Yichun topaz‐lepidolite granite is the youngest and most evolved unit of the Yichun granitic complex, southern China, and is well known by virtue of the unusual development of Ta‐Nb‐Li mineralization and enrichment in cesium in a granite. Three petrographic zones are recognized from the bottom upward: K-feldspar-rich facies, albite-rich facies, and albite- and K-feldsparrich facies. The Cs contents increase with fractional crystallization of the magma, and reach a maximum in the middle part of the albite-rich facies (1709 ppm). Two principal carriers of Cs are observed in this facies: pollucite and the Cs-dominant analogue of polylithionite. In the middle part of this facies, both minerals occur as small inclusions within quartz or K-feldspar phenocrysts, indicative of a magmatic origin. However, in the upper part of this facies, pollucite appears interstitially among tabular crystals of albite around K-feldspar phenocrysts, suggesting that this type of pollucite postdates the rock-forming minerals, but formed prior to complete crystallization of the silicate melt. In addition, Cs-rich replacement zones typify the rim of lepidolite flakes in the groundmass. Lepidolite may contain up to 25.8 wt% Cs2O, or ~0.9 Cs apfu (based on O = 11). Such lepidolite may be considered a Cs-dominant analogue of polylithionite. According to their distribution and compositional characteristics, pollucite and the Cs-dominant analogue of polylithionite seem to have formed at the late-magmatic or magmatic to hydrothermal transition stage of evolution of the leucogranitic magma at Yichun.
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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 | 0.001 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".