Abstract: Marine sediments formed during the Cenozoic Era are used to reconstruct the evolution of the ocean chemical and isotope composition. However many debates are still vigorous concerning both the estimated reconstructions and their interpretations. Large uncertainties therefore remain concerning the relationships between climate, carbon cycle and continental weathering during this period. I will present a new approach based on lithium isotopes measured in authigenic clays that challenges the classical view of the forcing parameters on the ocean's evolution.