Utilisation du10Be cosmogenique produit in-situ pour l'etude de la dynamique et de l'evolution des sols en milieux lateritiques

Abstract : In situ-produced cosmonuclides result from nuclear reactions between cosmic-rays derived particles and the elements constituting the Earth's surface material. Cosmogenic 10 Be (T½=1,5Ma) and 26 Al (T½ =0.73 Ma) produced within the quartz mineral fraction of surficial rocks have been used to quantitatively study the laterites emplacement and development. Depth distributions of in situ-produced 10 Be along quartz veins and soil profiles permit: 1/ to clarify mechanisms involved in soil formation and landform evolutions, 2/ to quantify burial or denudation rates. Lateral variations of the in situ-produced 10 Be concentration along stone-lines allow to determine whether the stone-line constituting material has an allochthonous or an autochthonous origin, and, in the later case, to estimate the lateral displacement rates.