Clay mineralogy of ODP Leg 103 sites (Table 1)

Samples from Cenozoic and Mesozoic sediments drilled during ODP Leg 103 were analyzed for clay mineralogy. Kaolinite, chlorite, illite, and smectite occur in most of the samples studied; palygorskite and sepiolite occur principally in Paleogene and Eocene brown clays. In general, throughout the section deposited in the syn- and post-rift period, the more calcareous-rich pelagic sediments contain greater amounts of smectite and lesser amounts of kaolinite and chlorite than do the calcareous-poor terrigenous sediments. The clay data presented here also lend support to the general paleoenvironmental interpretation of a relatively warm climate throughout the Cretaceous and early Tertiary and a relatively cooler climate from the Oligocene to the present day.