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doi:10.2204/iodp.proc.342.108.2014 Age-depth modelThe age-depth model is tied to Pleistocene to upper Eocene nannofossil datums in the upper 18 m of Hole U1407A. Through the middle Eocene, paleomagnetic datums are used as the primary tie points. Apart from a single radiolarian datum, the age-depth model is tied to nannofossil datums for the remainder of Hole U1407A, which ranges from lower Eocene to Albian. Good agreement exists between nannofossil datums and other datums over this interval. Clusters of nannofossil datums at two horizons in the lower Eocene served to identify two short hiatuses (49.5–51.5 and 54.4–55.6 Ma). The Maastrichtian and upper Campanian is also inferred to be extremely condensed from a series of closely spaced nannofossil datums between 186.65 and 206.57 mbsf. Linear sedimentation ratesBelow the condensed Pleistocene–Miocene interval in the upper 20 mbsf, LSRs in Hole U1407A are high in the middle Eocene (~2 cm/k.y.); moderately high in the Paleocene (1 cm/k.y.); and low in the uppermost Cretaceous and Miocene, Eocene, and Paleocene (0.2–0.9 cm/k.y.). Mass accumulation ratesMARs range from <0.1 g/cm2/k.y. in the Oligocene to Pleistocene to peak values of ~4 and 9 g/cm2/k.y. in the Cenomanian/Turonian boundary interval (~93 Ma) and during the early Eocene (~50 Ma), respectively. Carbonate contents dominate the sediment accumulation until the lower/middle Eocene boundary. After this time, carbonate and noncarbonate constituents accumulate at roughly equal rates. Peaks in MAR occur during the Turonian (~1 g/cm2/k.y.), the middle to late Paleocene (1–1.5 g/cm2/k.y.), and the middle Eocene (2.0 g/cm2/k.y.). |
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