Oligocene to Miocene stable isotope stratigraphy and planktonic foraminifer biostratigraphy of the Sierra Leone Rise (DSDP Site 366 and ODP Site 667)

Abstract

Deep Sea Drilling Project Site 366 recovered a record with a minor unconformity in the "middle' Oligocene and a condensed middle Miocene section. Ocean Drilling Program Site 667 recovered an apparently continuous "middle' Oligocene to lower middle Miocene record and a similar condensed middle Miocene section. The Oligocene to lower Miocene sections were deposited at similar sedimentation rates (~11-16 m/m/y.). In addition to earliest Oligocene and middle Miocene δ18O increases, a distinct δ18O increase occurred near the Oligocene/Miocene boundary. Carbon isotope variations provide similar potential for improving correlations. -from Authors