Eocene exhumation of the Tuareg Shield (Sahara, Africa)

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Authors
Rougier, S.
Missenard, Y.
Gautheron, C.
Barbarand, J.
Zeyan, H.
Pinna, R.
Liégeois, J.P.
Bonin, B.
Ouabadi, O.
Derder, M.E.M
Frizon de Lamotte, D.
Discipline
Earth and related Environmental sciences
Subject
Geodynamics and mineral resources
Audience
Scientific
Date
2013Publisher
Geological Society of America
Metadata
Show full item recordDescription
The arch-and-basin geometry that characterizes North Africa was achieved at the end of  Paleozoic times. It has been subsequently reactivated during the Mesozoic-Cenozoic with, in  particular, the development of large topographic anomalies. Among these, the Tuareg Shield  forms a topographic high in which the Pan-African basement reaches 2400 m above sea level  (Hoggar core). While Cretaceous sedimentary remnants suggest a possible stage of subsidence  during the Mesozoic, currently the area forms a swell, emphasized by Cenozoic volcanic episodes  since 35 Ma. In this context, we present the fi rst apatite (U-Th)/He thermochronological  data acquired across this swell, with mean ages ranging from 78 ± 22 Ma to 13 ± 3 Ma. These  results demonstrate the existence of a widespread Eocene exhumation of the shield before  volcanic activity began, which refl ects large-scale vertical processes. In the northeastern part  of the swell, Cretaceous continental sedimentary remnants unconformably lying on the basement  close to our samples evidence that they were near the surface at that time. This study  shows that basement rocks have undergone subsequent heating at ~60 80 °C, suggesting a  burial of more than 1 km after the Early Cretaceous. This conclusion can be possibly extended  over the whole Tuareg Shield
Citation
Rougier, S.; Missenard, Y.; Gautheron, C.; Barbarand, J.; Zeyan, H.; Pinna, R.; Liégeois, J.P.; Bonin, B.; Ouabadi, O.; Derder, M.E.M; Frizon de Lamotte, D. (2013). Eocene exhumation of the Tuareg Shield (Sahara, Africa). , Geology, Vol. 41, 615-618, Geological Society of America, DOI: 10.1130/G33731.1.Identifiers
Type
Article
Peer-Review
Yes
Language
eng
