Discussion on ‘From Pan-African transpression to Cadomian transtension at the West African margin: new U–Pb zircon ages from the Eastern Saghro Inlier (Anti-Atlas, Morocco)’ by Errami <i>et al</i> . 2020 ( <i>SP</i> 503, 209–233)
Bibliographic record
Abstract
An important paper has recently been published in Geological Society, London, Special Publications by Errami et al . (2020). On the basis of new U–Pb zircon radiometric data on magmatic and sedimentary rocks in the Saghro Massif, the authors revised the history of magmatic and geodynamic evolution of the Pan-African belts of the Moroccan Anti-Atlas along the northern edge of the West African Craton. The authors focused on the two main accretionary stages widely recognized in the Anti-Atlas (Ennih and Liegeois 2008; Gasquet et al. 2008): (1) a Paleoproterozoic episode, known as the Eburnean Orogeny, characterized by the extensive emplacement of granitoids at c. 2.1 − 2.0 Ga; (2) Neoproterozoic (800–450 Ma) events corresponding to the Pan-African Orogeny. However, in their lithostratigraphic framework of Proterozoic units of the Anti-Atlas, the authors do not account for the magmatic event recently recognized in several inliers in the Anti-Atlas (Fig. 1): Ighrem (Ikenne et al. 2017), Kerdous (Youbi et al. 2019) and Zenaga (Ait Lahna et al. 2020). Sills intrusive into the mixed carbonate–siliciclastic series of the Taghddout and Lkest groups, previously considered as Cryogenian, have been dated at between 1.7 and 1.6 Ga (Fig. 2). These new ages are c . 1 Ga older than previously thought, and call into question the stratigraphic position of the Tagdoute and Lkest groups in the southwestern domain of the Anti-Atlas. These series are now interpreted to be deposited in an intracratonic basin that developed after the assembly of the Nuna–Columbia supercontinent and before the break-up of the Rodinia supercontinent. The previous Cryogenian age for these deposits and their geodynamic setting thus need to be revised. Fig. 1. Geological map of the Anti-Atlas with the locations of the dated sills in the Ighrem, Kerdous and Zenaga inliers shown. SAF, South Atlas Fault; WAC, West African Craton; AVFZ, Ameln Valley Fault Zone; TTFZ, …
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".