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Results and correlation with the LR04 stack

A plot of δ18O versus depth shows a cyclic fluctuation between 1.32‰ and 4.11‰, whereas δ13C shows a cyclic fluctuation between –1.95‰ and 0.77‰ (Fig. F2). No samples of N. flemingi were found from 10.7 to 63.3 m CSF-A, but good δ18O and δ13C results were obtained from the rest of the section to 550 m CSF-A at intervals of ~1.5 m. The average sedimentation rate within the upper 550 m is estimated as 22 cm/1000 y (see the “Site U1352” chapter [Expedition 317 Scientists, 2011]). As a result, 1.5 m represents ~7000 y, and we are therefore confident that we can recognize δ18O and δ13C fluctuations with cycle periods exceeding ~14,000 y.

Results from coring (see the “Site U1352” chapter [Expedition 317 Scientists, 2011]) suggested that an unconformity lies somewhere between 491.74 and 525.34 m CSF-F, with a hiatus from 1.8 to 2.7 Ma. We use this correlation, together with the seven Pleistocene nannofossil datum levels that fall within the measured section (Table T3; see also the “Site U1352” chapter [Expedition 317 Scientists, 2011]), to correlate the δ18O record (Fig. F3A) to the global benthic foraminiferal δ18O LR04 stack of Lisiecki and Raymo (2005) (Fig. F3B) and to plot the Expedition 317 δ18O record versus age (Fig. F3C). Ultimately, we recognize all of the marine isotope stages (MIS) of the LR04 stack (Lisiecki and Raymo, 2005) except for MIS 3 and 4, which are expected to lie within the interval between 10.7 and 63.3 m CSF-A where N. flemingi was absent (Fig. F3C).

A depth-age curve (age model), based on the isotopic correlations, was generated using AnalySeries software (Fig. F4) and indicates that the average sedimentation rate in the upper ~500 m of Hole U1352B is ~28 cm/1000 y. However, sedimentation rates fluctuate; the maximum rate is ~60 cm/1000 y, and the minimum is <10 cm/1000 y.