REE concentrations and Nd isotopic compositions have been determined in Late Cretaceous-Early Cenozoic fish debris from West African and Israeli platform sediments and show a strong regional control independent of time, except for those from the Northern Morocco. It is suggested that, although diagenetic fluids do not contribute REE's directly to the phosphatic debris, they may significantly change the Ce anomaly and the ϵNd(T) value of the epicontinental seas, which, in turn, control the REE in marine phosphates. It is shown that, over the investigated period, the North Moroccan shelf seawater was progressively flushed by deep North-Atlantic water. ¿ American Geophysical Union 1988