Site 1195 was selected to provide a chronostratigraphy for Leg 194 that was more complete than one that could be obtained at locations proximal to carbonate shedding. The Site 1195 chronostratigraphy will be used to refine the chronostratigraphy from other Leg 194 sites through the correlation of seismic sequences through the regional seismic grid. A total of 27 calcareous nannofossil datums and 11 planktonic foraminifer datums were established for the 521-m-thick sequence of early Miocene to Pleistocene age drilled at Site 1195 (Fig. F14; Table T7) (see "Biostratigraphy and Paleoenvironments"). The magnetostratigraphy obtained at this site is in agreement with the biostratigraphic datums for the middle Miocene and early late Miocene intervals (see "Paleomagnetism"). However, the late Miocene to Pleistocene magnetostratigraphy suggests ages of up to 1 m.y. younger than the biostratigraphy (Fig. F14). The age model is constructed based on the biostratigraphic control points.
Given the larger benthic foraminifer assemblage, a piece of limestone in Unit V (518 mbsf), presumed to represent the top of the acoustic basement, may be late Eocene in age. However, the sample is surrounded with sediment containing nannofossils of early Miocene age, and the exact age of this horizon remains uncertain.
Miocene interval sedimentation rates vary between 13 and 67 m/m.y. (average 31 m/m.y.); Pliocene-Pleistocene rates vary between 10 and 23 m/m.y. (average 15 m/m.y.) (Fig. F14). No hiatuses were observed at the resolution of shipboard sampling.
Age picks for lithologic and seismic unit boundaries are summarized in Table T8.