In recent years there has been considerable discussion concerning the biostratigraphic correlations between planktonic zonations and the classical Neogene California benthic foraminiferal stages. One of the primary objectives of IPOD Leg 63 was to explore these correlations and to determine the possibility of temporal variation of the benthic stages between the outer continental borderland and land sections.

Site 468 was drilled on the Patton Escarpment, which lies under the present southeastern margin of the California current system. The sediments yielded well-preserved calcareous and siliceous planktonic assemblages that ranged in age from Holocene to middle Miocene. Samples also contain abundant benthic foraminiferal assemblages that consist of species characteristic of both oceanic and continental margin environments.

The benthic foraminiferal assemblages range from the Venturian stage of the Pleistocene to the Luisian-Relizian stages of the middle Miocene. Because of the dependence of benthic species on bottom environmental parameters, the dominant occurrence of lower bathyal to abyssal faunas present problems for direct correlations to local California stages. The majority of key species needed for recognition of the late and middle Miocene benthic stages, as defined in land sections, are indicative of upper to middle bathyal environments and are excluded from the deeper habitats because of environmental restrictions. The occurrence of the lower bathyal pseudo-Saucesian assemblage as a major faunal constituent in the late and middle Miocene samples furthers adds to the complexity of correlations etween the planktonic zonations and benthic foraminiferal stages.

End_of_Article - Last_Page 902------------