Répertoire du personnel
Jean-Paul Liégeois
Sciences de la Terre
Géodynamique et ressources minérales
Géodynamique et ressources minérales
Détails
Abdelsalam, M.G., Liégeois, J.P. & Stern., R.J. 2001. ‘The Saharan Metacraton’. Journal of African Earth Sciences 34: 119-136. Amsterdam : Elsevier. I.F. 1.219.
Article dans une revue scientifique / Article dans un périodique
Abstract - This article introduces the name "Saharan Metacraton" to refer to the pre-Neoproterozoic - but sometimes highly remobilized during Neoproterozoic time - continental crust which occupies the north-central part of Africa and extends in the Saharan Desert in Egypt, Libya, Sudan, Chad and Niger and the Savannah belt in Sudan, Kenya, Uganda, Congo, Central African Republic and Cameroon. This poorly known tract of continental crust occupies ~5,000,000 km2 and extends from the Arabian-Nubian Shield in the east to the Tuareg Shield to the west and from the Congo craton in the south to the Phanerozoic cover of the northern margin of the African continent in southern Egypt and Libya. The term "metacraton" refers to a craton that has been remobilized during an orogenic event but is still recognizable dominantly through its rheological, geochronological and isotopic characteristics. Neoproterozoic remobilization of the Saharan Metacraton was in the forms of deformation, metamorphism, emplacement of igneous bodies, and probably local episodes of crust formation related to rifting and oceanic basins development. Relics of unaffected or weakly remobilized old lithosphere are known. The article explains why the name "Saharan Metacraton" should be used, defines the boundaries of the metacraton, reviews geochronological and isotopic data as evidence for the presence of a pre-Neoproterozoic continental crust, and discusses what happen to the Saharan Metacraton during the Neoproterozoic. A model combining collisional processes, lithospheric delamination, regional extension, and post-collisional dismembering by horizontal shearing is proposed.