Staff directory
Jean-Paul Liégeois
Earth Sciences
Geodynamics and mineral resources
Geodynamics and mineral resources
Publication details
Bouzid, A., Bayou, B., Liégeois, J.P., Bourouis, S., Bougchiche, S.S., Bendekkem, A., Abtout, A., Boukhlouf, W. & Ouabadi, A. 2015. ‘Lithospheric structure of the Atakor metacratonic volcanic swell (Hoggar, Tuareg Shield, southern Algeria): Electrical constraints from magnetotelluric data’. In: Foulger, G.R., Lustrino, M., and King, S.D. (ed), The Interdisciplinary Earth: A Volume in Honor of Don L. Anderson. Series ‘Geological Society of America Special Paper’, 714. Boulder : Geological Society of America. (PR) DOI: 10.1130/2015.2514(15)..
Chapter in an edited book / Article in an edited book
The Tuareg Shield, to which Hoggar (southern Algeria) belongs, has a swellshaped
morphology of lithospheric scale of ~1000 km in diameter linked to Cenozoic
volcanism occurring in several regions, including Atakor, the center of the swell,
which reaches nearly 3000 m in altitude. The lack of high-resolution geophysical data
for constraining its deep structure is at the origin of a controversy about its innermost
nature and about the origin of the Cenozoic volcanism. During the course of
this study, magnetotelluric (MT) broadband data were collected at 18 sites forming
a northeast-southwest profi le 170 km long within the Atakor region. The electrical
resistivity model obtained by inverting the magnetotelluric data reveals lithospheric
structure down to a depth of ~100 km. From this depth to the surface, the model does
not show any regional anomaly that may result from a metasomatized lithosphere or from an asthenospheric upwelling, including a mantle plume. MT data reveal
rather a lithosphere affected by a set of rather thin subvertical conductors that can
be attributed to the electrical signature of some known shear zones resulting from the
Pan-African evolution of the LATEA metacraton, which globally corresponds to the
uplifted Central Hoggar swell. The main anomaly is deeply rooted in the lithosphere
and underlies the Atakor-Manzaz volcanic districts. As a whole, MT data are therefore
properly integrated within the hypothesis of the reactivation of shear zones due
the intraplate deformation related to the collision between Africa and Europe since
the Eocene, applied onto the metacratonic region.