Orogenic growth in the atlas mountains of SW Marocco - Insights from low-temperature thermochronometry and in situ cosmogenic dating
Responsable du projet Angelika Kalt
Susan Ivy Ochs
Rainer Wieler
Résumé New U-Th/He data on apatites from the High Atlas of SW Morocco provide for the first time constraints on the exhumation history of the Atlas chain. U-Th/He ages on apatite range between 37 and 14 Ma for the axial zone of the High Atlas, between 39 and 13 Ma in the Sub-Atlas Zones and finally between 125 and 120 Ma in the Anti-Atlas. Age-altitude relationships in the axial zone of the High-Atlas suggest that exhumation attained 0.2 km/my for the Middle Miocene whereas the Anti-Atlas belt to the south either 1) did not undergo any protracted phase since the Late Jurassic-Early Cretaceous, or 2) undergoes such phase very recently that cannot be traced even with the lowest-temperature thermochronometer (U-Th/He on apatite). Preliminary data from the Sub-Atlas zones on both sides of the High-Atlas indicate that a 2-3 kms thick sedimentary pile of post-Cretaceous age is missing. The timing of this erosion is still unknown but will be constrained by thermal modeling through future Apatite Fission-Track and additional U-Th/He data, whereas sub-recent erosion rates are being determined by the production of in situ cosmogenic analyses on present-day river sands.
Mots-clés uplift, erosion, exhumation, neotectonics, north-africa, marocco, Denudation, Morocco, Anti- and High-Atlas, Tectonics, Fission-Track - and (U-Th)/He Thermochronometry, in situ cosmogenic exposure dating, North Africa, Anti-Atlas, High Atlas, fission track dating, (U-Th)/He thermochronometry, in-situ cosmogenic exposure dating
Type de projet Recherche fondamentale
Domaine de recherche Géologie
Source de financement FNS - Encouragement de projets (Div. I-III)
Etat Terminé
Début de projet 1-10-2006
Fin du projet 30-9-2008
Budget alloué 262'455.56
Contact Angelika Kalt