LAUSR

We generated clay mineral assemblage records on Late Cretaceous to Miocene-Pliocene rocks and on Holocene river sediments at Tarfaya Atlantic coastal basin in Morocco. Results show that illite, chlorite, kaolinite, smectite, and palygorskite originated from a continental source whereas corrensite formed within the basin. A very high kaolinite content and kaolinite/(illite+chlorite) ratio during the Turonian indicate a high chemical weathering which was coeval with a global weathering event during a warm and humid climate during that time. An increase in physical erosion during the Santonian as reflected by high (illite+chlorite) content and low kaolinite/(illite+chlorite) ratio was most likely associated with the early western Anti-Atlas uplift. Abundant (palygorskite+sepiolite) contents in Early Eocene rocks reflect the development of extremely dry and warm climatic conditions over the coastal regions of Tarfaya during that time. Dominant (illite+chlorite) and smectite clay minerals and a marked increase in sedimentation during the Miocene-Pliocene suggest an increase in physical erosion of the high-relief source region (western Anti-Atlas) which was mainly controlled by tectonic denudation. High kaolinite content and kaolinite/(illite+chlorite) ratio also occurred in the Holocene river sediments indicating warm and humid climate during that time. The abundant corrensite, however, indicates a basin depositional environment and suggests that oxic conditions were dominant in the Tarfaya basin during the Campanian and the Oligocene-Early Miocene.