Magnetic susceptibility (MS) and point sediment lightness (L*) data collected from Holes 1264A and 1264B at 2.5-cm intervals were used to construct the composite section for Site 1264 (Figs. F4, F5). The 600 nm (orange) to 450 nm (blue) ratio of the color reflectance data was primarily used for core-to-core correlation and to construct the composite section in the carbonate-rich sediments from ~25–130 meters composite depth (mcd). The depth offsets that define the composite section for Site 1264 are given in Table T2.
The composite depths of Cores 208-1264A-26H, 208-1264B-27H, 208-1264A-28H, and 208-1264B-29H were calculated using 11% and 12% growth rates for the mcd scale relative to the mbsf scale of Holes 1264A and 1264B, respectively (Fig. F6). This rate is based on the correlation of Cores 208-1264A-1H through 25H and 208-1264B-1H through 25H in the depth interval from 0 to 260 mcd. The composite data show that the cores from Site 1264 provide an almost continuous sequence from the seafloor down to 316.5 mcd, the lower Oligocene (Core 208-1264A-30H). Following construction of the composite depth section for Site 1264, a single spliced record was assembled from the aligned core intervals from the two parallel holes (Table T3). The presence of short cores (208-1264A-25H, 27H, and 28H) and a lack of overlap between the base of Core 208-1264A-29H and the top of Core 208-1264B-30H cause four gaps to occur in the spliced record. These gaps were bridged by applying the average growth rate of 14% to the core-top depths in mbsf. Most of the cores were not significantly stretched, squeezed, or disturbed by the coring process, and as a result, the color and MS cycles were reasonably well aligned between holes (e.g., Fig. F4), although the mcd values of the same stratigraphic horizon in alternate holes may not be exactly the same.
The O/M boundary interval in the composite was taken from Core 208-1264B-25H. The Site 1264 splice (Table T3) can be used as a guide to sample a single sedimentary sequence between the seafloor and 316 mcd and was used to plot other data sets from this site.