Unconformities and changes in sedimentation rate at Site 1213 are illustrated in a plot of calcareous microfossil datum ages (FOs and LOs) vs. depth (Fig. F27). These rates rely on major calcareous nannofossil and planktonic foraminiferal datums presented in Tables T5 and T6 (see "Biostratigraphy"). The Pleistocene-basal Cretaceous or uppermost Jurassic section cored at Site 1213 is punctuated by at least two unconformities separating the lower Pliocene and lower Santonian and the lower Santonian and mid- to upper Cenomanian.
An expanded view of the Neogene (Fig. F28) shows that the mid- to lower Pliocene section accumulated at a rate of ~5.5 m/m.y., increasing to 14.6 m/m.y. in the upper Pliocene-Pleistocene. Dark-colored clay-rich sediments in Core 198-1213A-6R record condensed basal Pliocene (and upper Miocene?) sedimentation overlying the major upper Neogene/Upper Cretaceous unconformity (Figs. F28, F29).
Core 198-1213A-7R contains <1 m of lower Santonian chalk bounded by two major unconformities, with lower Pliocene (and upper Miocene?) above and mid- to upper Cenomanian below (Fig. F29). Core recovery was poor throughout the Cretaceous section, but all cores yielded datable calcareous nannofossil assemblages, which were supported by planktonic foraminifers and/or radiolarians (see "Biostratigraphy"). The mid-Cenomanian-upper Albian sediments accumulated at an average rate of 21.2 m/m.y. The interval from near OAE1a in the lower Aptian through the middle Albian accumulated at a reduced rate of 4.7 m/m.y. The basal Aptian-upper Hauterivian is either missing at Site 1213 or is represented by an unrecovered condensed interval (sedimentation rates of ~1.1 m/m.y.). Sedimentation rate estimates for the lower Hauterivian-Berriasian interval range between 12.3 and 16.2 m/m.y. based on the combined evidence of calcareous nannofossils, radiolarians, and planktonic foraminifers (Fig. F29).