Stable carbon and oxygen isotope record of planktonic foraminifera of ODP Hole 115-709C

A closely spaced (5-cm interval) oxygen isotope stratigraphy of planktonic foraminifers from Hole 709C was completed for most of the Pliocene and lowermost Pleistocene (around 4.6-1.4 Ma). This will contribute data to the future testing of the Matthews and Poore model of 1980, in which it was assumed that low-latitude sea-surface temperature has remained virtually constant as global climate evolved.
Spectral analyses of the record by means of biostratigraphic time controls show a distinct peak at a period near 40 ka that is probably associated with the orbital obliquity cycle. Visual inspection of the record shows that intervals containing distinct 40-ka cycles are present in both lower and upper parts of the Pliocene even though a regular cycle cannot be followed throughout the entire 4-m.y. investigated.