The composite section for Site 1119 was constructed using data from Holes 1119B and 1119C, which penetrated to 155.54 and 494.40 mbsf, respectively. Magnetic susceptibility (MS) and natural gamma-ray intensity (NGR), both measured on whole cores on the MST, formed the primary data sets used for correlation. Other high-resolution data sets were unsuitable for correlations at this site. The P-wave velocity measurements suffered from pervasive gas voids and were determined consistently only in the APC cores from Hole 1119C. GRAPE values showed low-amplitude variation and were difficult to correlate among holes. Split-core reflectance measurements displayed considerable mean offsets between holes as well as poor reproducibility.
The composite section was constructed by aligning the unsmoothed MS data (measured at 4-cm intervals) for Cores 181-1119B-1H to 12H and 181-1119C-1H to 12H. Below this, to the base of Hole 1119B, unsmoothed NGR data (measured at 14- to 16-cm intervals) provided an extra guide to correlation (Cores 181-1119B-13H to 17H and 181-1119C-13H to 17H). Figure F17 illustrates the final composite section alignments. Documented continuous overlap between the two holes extends down to 90 meters composite depth (mcd). Gaps in the sedimentary sequence, with no overlap between holes, occurred between Cores 181-1119C-9H and 10H, 181-1119C-10H and 11H, 181-1119C-15H and 16H, and 181-1119C-16H and 17H (Fig. F17). In these cases, we assigned the top of the deeper core in one hole an mcd value equal to that at the base of the overlying core in the other hole. Table T10 (also in ASCII format) contains the offsets between the mbsf and mcd scales resulting from composite section construction. In general, the offsets roughly follow a linear downhole trend, with mcd depths increasing at a rate of ~10% over mbsf depths (Fig. F18). Composite depth sections commonly display such "stretching" on the order of 10% (e.g., Curry, Shackleton, Richter, et al., 1995).
The spliced record (Fig. F19), defining a nearly complete sedimentary sequence, extends to 172 mcd. Wherever possible, splice tie points (Table T11, also in ASCII format) were picked at well-defined maxima or minima where the overlap in data from Holes 1119B and 1119C are correlated. Typically parameter values differed by less than 10% at tie levels and the correlation coefficient within a 2-m window often exceeded 0.6. In all cases, ties were selected so that the spliced record was as free from noise (high-frequency variability) as possible.