LP-HT metamorphism in the Jebilet Massif (Moroccan variscan belt): from Paleothetys opening to Pangea formation
Bibliographic record
Abstract
In the westernmost part of the Variscan belt, petro-structural observations, mineral equilibria modelling and U-Pb age determination were carried in the Jebilet massif (Morocco), in order to precise the deformation–metamorphism of NW Africa during Late Paleozoic Variscan events. A first episode corresponds to the emplacement of the main Oulad Ouaslam intrusion at 335.2 ± 0.8 Ma (U-Pb LA-ICP MS on zircon) within a Visean intracontinental basin. A second episode correspond S to SE convergence resulting into nappe stacking and upright folding in the supracrustal level together with the progressive development of a sub-horizontal metamorphic foliation around the pre-heated pelitic country rocks of the intrusion up to the sillimanite zone. Crd-And growth during this event in metapelite indicate indicating heating and increase of pressure up to 600–625 °C and 1.6–2.0 kbar. The timing of this sequence in metapelite is constrained by the U-Pb monazite age of 323.4 ± 3.6 Ma, interpreted as minimum age of metamorphic peak conditions, ca. <15 Ma younger than the emplacement of the intrusion. This very moderate thickening is followed by WNW convergence, sub-orthogonal to the first one, affecting all the previous structures and continuing probably up to the Cisuralian, similar to neighboring massifs. The first episode coincides with emplacement of magma within Visean intracontinental basins at the western tip of the ongoing opening Palaeo-Tethys Ocean, whereas the monazite dating document for the first time the precocious onset, during Late Serpukhovian–Early Bashkirian of the convergence in the NW African Variscan segment.
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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 | 0.001 | 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) | 0.002 | 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 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".