OCCURRENCE OF PREHNITE, PUMPELLYITE AND GARNET IN BIOTITE FROM GRANITIC ROCKS OF THE CANADIAN APPALACHIANS: A MINERAL CHEMISTRY STUDY USING ELECTRON MICROPROBE
Bibliographic record
Abstract
A particular feature of biotite grains from some of the Canadian Appalachian granitic rocks is the presence of lenses of Ca-Al silicates developed along cleavage planes. These from the more to less common are prehnite, pumpellyite and grandite garnet, an intermediate composition between andradite and grossular. Rarely all three minerals can be observed together in one single biotite grain. Microprobe analyses show that Al2O3 contents of prehnite vary from 17.52 to 24.55 and Fe2O3 from 2.38 to 8.88 wt. %, which can be reflected in a substantial and variable substitution of Fe for Al. Furthermore, a fairly positive correlation of MnO values of both prehnite and host biotite may indicate the role of biotite replacement by prehnite. Fe2O3 content in nine analyzed pumpellyite samples varies between 10 and 23 wt%. Fe2O3 contents of more than 10 wt% in pumpellyite are indicative of zeolite and prehnite-pumpellyite facies conditions.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 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".