TS6.4

Cratons and surrounding mobile belts: evolution, interplay and interferences. The West African case study
Convener: Lenka Baratoux  | Co-Conveners: Jean-Paul Liegeois , Mark Jessell 
Oral Programme
 / Fri, 07 May, 15:30–17:00  / Room 32
Poster Programme
 / Attendance Fri, 07 May, 10:30–12:00  / Hall A
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The recent accumulation of metamorphic, geochronological and geophysical data across the West African Craton and its margins allows us to take a fresh look at this ancient terrain. This session will focus on the craton-scale evidence for the formation and evolution of the craton during the Archaean and Palaeoproterozoic, as well as its subsequent modification by the Pan-African Mobile Belts. An understanding of the processes of cratonization and characterization of major Archaean and Eburnean structures is crucial for determination of pre-existing crustal inhomogeneities susceptible to be reactivated during the Pan-African orogeny. Conversely we also need to constrain precisely the deformation features in the Pan-African orogens, so we can better determine the penetration of this event into the craton. Relations between the Archaean/Palaeoproterozoic domains present in the West African craton and in the surrounding mobile belts, especially the Trans-Saharan belt have also to be deciphered.
The great advantage of West Africa is that we can observe and describe processes leading to the formation of Archaean and Palaeoproterozoic terranes cratonized during the long Mesoproterozoic tectonic quiescence and then largely well preserved. Their reactivations occurred only during the Neoproterozoic Pan-African orogeny, generating for instance a strong and useful isotopic constrast.
Contributions are welcome on all aspects of research providing new insights into the evolution of the West African craton, and/or its subsequent modification during the Pan-African as well as of the surrounding mobile belts. Comparisons with similar problematic outside of West Africa are also welcome.