ALLANITE-(Ce) FROM THE EOCENE CASTO GRANITE, IDAHO: RESPONSE TO HYDROTHERMAL ALTERATION
Bibliographic record
Abstract
The response of allanite-(Ce) in the Eocene Casto granite of Idaho to hydrothermal activity has been investigated. Unaltered, igneous allanite from the Casto pluton is characterized by a narrow range of compositional variation, with little or no zoning. A representative empirical formula, based on the composition of the least-altered grain, is: (REE0.83Ca1.07Th0.04Mn2+0.06) (Ti4+0.11 Mg2+0.04Fe2+0.99Fe3+0.48Al1.38) (Si3.00O12) (OH0.95F0.05), where REE represents (La0.14Ce0.41Pr0.05Nd0.17Sm0.03Y0.03). The small amount of observed compositional variation is consistent with the coupled substitutions Ca2+ + Th4+ $ 2REE3+ and REE3+ + Fe2+ + Mg2+ $ Ca2+ + Al3+ + Fe3+. Slightly altered crystals exhibit a rim in which Th is enriched, and La and Ce are depleted. Increasing alteration lead to extensive corrosion and replacement of allanite by fluorite, a REE-, Th- and P-rich phase (probably monazite), and a Th-rich phase (probably thorianite). In spite of attack by fluoride-rich hydrothermal solutions, the REE and Th originally in allanite were not transported significant distances, but were redeposited locally as secondary phases. The lack of significant REE and Th transport is due to the availability of phosphorus, which allowed the REE to be fixed in a secondary phosphate phase, and the removal of fluoride as fluorite. This work has implications for the behavior of radioactive waste in deeply buried geological repositories upon interaction with heated groundwaters.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.041 | 0.002 |
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; both teacher heads agree on what is shown here.
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".