THE DISTRIBUTION OF RARE-EARTH ELEMENTS IN K-FELDSPAR AS AN INDICATOR OF PETROGENETIC PROCESSES IN GRANITIC PEGMATITES: EXAMPLES FROM TWO PEGMATITE FIELDS IN SOUTHERN NORWAY
Bibliographic record
Abstract
The K-feldspar from strongly zoned gadolinite-type REE–Nb–Ta-rich granitic pegmatites from the Evje–Iveland and Froland pegmatite fields in southern Norway was analyzed for the entire spectrum of rare-earth elements, as well as for a suite of majo r and trace elements, with the HR–LA–ICP–MS technique. Earlier results imply that the two pegmatite fields are nearly indistinguishable in terms of their origin and igneous evolution. An evaluation of the distribution of K, Rb, Sr and Ba in Kfeldspar, elements that are strongly sensitive to igneous processes in felsic rocks, confirm this conclusion. However, the distribution of the ultra-trace elements, and particularly the REE, in K-feldspar is incompatible with a common origin of the two fields. The REE distribution in K-feldspar is buffered by the coexisting REE-phases. When compared to Evje–Iveland, the Froland suite of pegmatites was derived from a relatively LREE-deficient and HREE-enriched parent melt. Finally, the distribution of trace elements in feldspar implies that the Evje–Iveland pegmatites formed from progressively more differentiated melts that were emplaced in a southward-propagating system of vertical and horizontal faults and fractures.
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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 | 0.001 |
| 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) | 0.002 | 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".