%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Moussa, A.
%A Novello, A.
%A Lebatard, A. E.
%A Decarreau, A.
%A Fontaine, C.
%A Barboni, D.
%A Sylvestre, Florence
%A Bourles, D. L.
%A Pailles, C.
%A Buchet, G.
%A Duringer, P.
%A Ghienne, J. F.
%A Maley, J.
%A Mazur, J. C.
%A Roquin, C.
%A Schuster, M.
%A Vignaud, P.
%A Brunet, M.
%T Lake Chad sedimentation and environments during the late Miocene and Pliocene : new evidence from mineralogy and chemistry of the Bol core sediments
%D 2016
%L fdi:010067631
%G ENG
%J Journal of African Earth Sciences
%@ 1464-343X
%K Lake Chad ; Miocene-Pliocene ; Fe-beidellite ; Vertisol ; Sedimentation rate
%K TCHAD
%M ISI:000378434500016
%P 192-204
%R 10.1016/j.jafrearsci.2016.02.023
%U https://www.documentation.ird.fr/hor/fdi:010067631
%> https://www.documentation.ird.fr/intranet/publi/2016/08/010067631.pdf
%V 118
%W Horizon (IRD)
%X This study presents mineralogical and geochemical data from a borehole drilled near the locality of Bol (13 degrees 27'N, 14 degrees 44'E), in the eastern archipelago of the modern Lake Chad (Chad). Samples were taken from a similar to 200 m long core section forming a unique sub-continuous record for Central Africa. Among these samples, 25 are dated between 6.4 and 2.4 Ma. Dominant minerals are clays (66% average) mixed with varying amounts of silt and diatomite. The clay fraction consists of Fe-beidellite (87% average), kaolinite, and traces of illite. Clay minerals originate from the erosion of the vertisols that surrounded the paleolake Chad. Sedimentological data indicate that a permanent lake (or recurrent lakes) existed from 6.7 until 2.4 Ma in the vicinity of Bol. By comparison with modern latitudinal distribution of vertisols in Africa the climate was Sudanian-like. Changes in the sedimentation rate suggest a succession of wetter and dryer periods during at least six million years in the region during the critical time period covering the Miocene-Pliocene transition.
%$ 064 ; 068