Cretaceous crustal thinning in North Africa : Implications for magmatic and thermal events in the Eastern Tunisian margin and the Pelagic Sea

H. Mattoussi Kort (1) , Dominique Gasquet (2) , M. Ikenne (3) , N. Laridhi Ouazza (4)

1 Unité de Pétrologie Cristalline et Sédimentaire
2 EDYTEM - Environnements, Dynamiques et Territoires de Montagne
3 Département de Géologic
4 Département de Géologie

The integrated use of geological, geophysical, and geochemical data from Eastern Tunisia onshore and off- 24 shore samples indicate a crustal thinning induced from the Tethyan rifting. This is responsible for the 25 subsequent evolution of the North African passive margin during the Late Cretaceous, and the creation 26 of the fold–thrust belt and associated foreland deformations. This thinned crust was an area of mantle 27 upwelling that favoured the increase of isotherms, the uprise of basalt magma, and the circulation of 28 hydrothermal fluids. The Cretaceous magmatism generated a major hydrothermal event characterised 29 by the circulation of hot fluids along faults and a relatively high heat flow in the basin. Temperature ele- 30 vation and hydrothermal conditions led to alteration of basalts and generated a new mineral equilibrium 31 around the enclosing sedimentary deposits.

Domaines: Milieux et Changements globaux

H. Mattoussi Kort, Dominique Gasquet, M. Ikenne, N. Laridhi Ouazza. Cretaceous crustal thinning in North Africa : Implications for magmatic and thermal events in the Eastern Tunisian margin and the Pelagic Sea. Journal of African Earth Sciences, 2009, in press. ⟨halsde-00391914⟩