Controls on REE mineralization in the Tioueine ring complex (Western Hoggar, Algeria): examination of magmatic vs hydrothermal processes
Bibliographic record
Abstract
The Hoggar is a rare metal endowed province within the Tuareg shield with variably mineralized post Pan-African granitoid complexes. The investigated Tioueine Ring Complex is among them, with two major units: a weakly evolved calc-alkaline central unit containing monzogranite and granodiorite, and a highly evolved alkali feldspar granite-dominated major outer unit that hosts magmatic to magmatic-hydrothermal LREE-dominant mineralization. The Tioueine Ring Complex is a mantle-derived A 1 -type granitoid complex that crystallized at ca. 600 Ma during a post-orogenic to anorogenic episode of the Pan-African orogeny. Its parental magmatic system is characterized by high concentrations of alkali elements, with moderate total REE 2 O 3 (TREE 2 O 3 ) contents up to 0.2 wt%; allanite is the major REE-rich mineral, with limited proportions of apatite, xenotime, and rare monazite. Primary mineralization resulted from low degrees of partial melting of an enriched mantle source that produced reduced ferroan REE-rich magma following advective mantle heat input. The derivative melt may have experienced crustal assimilation and crystal fractionation that caused further enrichment in HFSE and REE before reaching the solidus. A late- to post-magmatic-hydrothermal event allowed limited secondary enrichment of REE by causing allanite breakdown to form REE-fluorocarbonate minerals. Fluid—rock interaction likely resulted from magmatic-hydrothermal F- and CO 2 -rich aqueous fluids and late meteoric hydrothermal fluids that circulated through ring faults. The Tioueine Ring Complex exhibits elevated REE concentrations that warrant follow-up sampling and drilling to assess its economic viability. However, despite REE enrichment in A-type granites globally, the role of F-rich fluids in remobilizing REE from magmatic allanite to form hydrothermal REE-fluorocarbonates remains poorly constrained. The Tioueine Ring Complex offers a case study to elucidate this process.
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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 | 0.000 |
| 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) | 0.000 | 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".