Magnetic susceptibility (MS) and sediment lightness (L*) data (600 nm/450 nm ratio) collected from Holes 1265A, 1265B, 1265C, and 1265D at 2.5-cm intervals were used to correlate cores and to construct the composite section for Site 1265. Multisensor track (MST) data were collected at 5-cm intervals from 0 to 105 mbsf in Holes 1265A and 1265B. In the carbonate-rich sediments from ~10 to 30 mcd, only the 600 nm/450 nm ratio (orange/blue ratio) provided a signal-to-noise ratio suitable for correlation between holes (Figs. F4, F5). The depth offsets that define the composite section for Site 1265 are given in Table T2.
The composite depths of Cores 208-1265A-30H through 36X were calculated using a 14% meters composite depth (mcd) growth rate obtained from Holes 1265A and 1265B (Fig. F6). This growth rate is based on the correlation of Cores 208-1265A-1H through 27H and 208-1265B-1H through 27H in the depth interval of 0–295 mcd. The composite data show that the cores from Site 1265 provide an almost continuous stratigraphic sequence from the seafloor to 316 mcd, the upper Paleocene (Core 208-1265A-29H). Following construction of the composite depth section for Site 1265, a single spliced record was assembled from the aligned core records from the four parallel holes (Table T3). The lack of overlap between the base of Core 208-1265A-27H and the top of Core 208-1265B-28H and between Cores 208-1265D-2X and 208-1265A-29H resulted in two gaps in the spliced record. Most of the cores were not significantly stretched, squeezed, or disturbed by the coring process. As a result, the color and MS cycles were reasonably well aligned between holes (e.g., Figs. F4, F5), although the mcd values of the same stratigraphic horizon in alternate holes may not be exactly the same.
The P/E boundary interval in the composite was taken from Core 208-1265A-29H. The Site 1265 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.