Halogen-Bearing Minerals From the Tamazeght Complex (Morocco): Constraints On Halogen Distribution and Evolution In Alkaline To Peralkaline Magmatic Systems
Bibliographic record
Abstract
Abstract Halogen abundances in apatite, biotite, amphibole, titanite, and other halogen-rich minerals (sodalite and eudialyte) from ultramafic pyroxenites and glimmerites, shonkinites, and gabbroic, monzonitic, and syenitic rocks of the alkaline to peralkaline Tamazeght complex (Morocco) are presented. Apatite, biotite, and amphibole show the highest F contents in the most evolved rocks, which also contain interstitial fluorite (restricted in syenites). The Cl contents of apatite, biotite, and amphibole are highest in the intermediate rocks. Sodalite (Cl-rich) is equally common in the evolved rocks, although Cl contents of apatite, biotite, and amphibole are low. We suggest that the early magmatic crystallization of sodalite causes a strong depletion of Cl in the remaining melt, resulting in the subsequent crystallization of Cl-poor apatite, biotite, and amphibole. Late-magmatic eudialyte in some of the rocks may indicate a late-stage re-enrichment of Cl. The Br contents of biotite, amphibole, eudialyte, and sodalite reveal that Cl-rich minerals generally contain high Br. The Cl/Br ratios of individual minerals are, however, highly variable. This suggests that besides melt composition, other factors, such as crystal-melt partitioning and fluid mobility, may influence Cl/Br ratios in igneous minerals, resulting in potentially strong fractionation of Cl from Br in minerals. Estimation of F and Cl contents in alkaline melts suggests that primitive ultramafic melts are poorer in Cl than evolved melts, whereas their F contents are relatively similar. The low apparent Cl contents of the syenitic melts, calculated based on apatite compositions, may reflect the halogen abundance during late-magmatic conditions, as the presence of early magmatic sodalite indicates Cl-rich syenitic melt compositions.
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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 | 0.001 | 0.000 |
| 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".