Two composite depth scales were developed for Sites 1098 and 1099 based on correlation between spectral reflectance, GRAPE density, natural gamma ray, magnetic susceptibility, and P-wave velocity data (see "Physical Properties," and "Lithostratigraphy," "Composite Depths," in the "Explanatory Notes" chapter). The correlated section lies mainly within the Holocene, with recovery of ~100% for all holes. All parameters (except for P-wave data in Hole 1099B) were measured to 44.98, 44.10, and 45.12 mbsf in Holes 1098A, 1098B, and 1098C, respectively, and as much as 62.38 and 107.62 mbsf in Holes 1099A and 1099B. One composite section for each site was developed, which must be considered preliminary (see also "Composite Depths" in the "Explanatory Notes" chapter). The base of the Site 1098 composite section is at 46.94 meters composite depth (mcd), and the base of the Site 1099 composite section is at 107.94 mcd. The depth offsets that were used to calculate the composite depth sections are given in Table T30. Recovery at Site 1098 was remarkably continuous except for gaps between 1.67 and 1.96, 20.22 and 20.98, and 38.82 and 39.98 mbsf in Hole 1098A; between 5.76 and 6.10, and 34.02 and 34.58 mbsf in Hole 1098B; and between 8.34 and 8.76 mbsf in Hole 1098C. Similar continuity was found at Site 1099 except for three gaps between depths 33.95 and 35.38 mbsf in Hole 1099A and between 77.82 and 79.12, and 97.57 and 98.08 mbsf in Hole 1099B. It was therefore possible to obtain a continuous sedimentary sequence for Site 1098 using the data from the three holes. At Site 1099, however, the overlap between Holes 1099A and 1099B was only 2.22 m, so the successive cores in 1099B, below the overlap, were placed at their original depth (mbsf) corrected by addition of the accumulated offset from the upper part of the section.

Chromaticity parameters a* and b* were measured at intervals of 1 cm in Hole 1098A, 2 cm in Holes 1098B and 1098C and in the first 27 mbsf of Hole 1099A, and at intervals of 5 cm in the remaining part of Holes 1099A and 1099B. These data were used at both sites as primary correlation parameters (see "Composite Depths" in the "Explanatory Notes" chapter); GRAPE density and magnetic susceptibility were the other primary parameters used for correlation at Sites 1098 and 1099, respectively.

Magnetic susceptibility was not employed as a primary parameter at Site 1098 because the data show broad scale changes. This effect probably resulted from lithologic and diagenetic changes (see "Physical Properties"), which made splicer correlation with other parameters uncertain. Natural gamma ray and P-wave measurements provided supplementary verification of core overlap and depth offset.

The two principal parameters of the MST records that were useful in correlation are displayed on the composite depth scales in Figures F34 and F35. No smoothing or culling was applied to the data (except for GRAPE density at values lower than one). The correlations between GRAPE density, color reflectance (chromaticity parameter a*), natural gamma ray, and magnetic susceptibility for Sites 1098 and 1099 are shown in Figures F36 and F37. At Site 1098, we found that all data were well correlated in the first 6.5 mcd, revealing a cyclic pattern with a wavelength of ~60 cm. Color reflectance and GRAPE data were correlated down to 12.5 mcd. Below this depth, the data seem not to correlate except for three intervals: from 25 to 30 mcd (color reflectance and GRAPE density), from ~32 to 34 mcd (magnetic susceptibility, GRAPE density, and natural gamma ray data), and from ~41.5 to 43.5 mcd (inverse correlation between magnetic susceptibility and color reflectance).

At Site 1099, the upper 15 mcd seem to show a cyclic pattern with a wavelength of 2.5 m. Below this depth down to 60 mcd, mostly inverse or no correlation was observed between magnetic susceptibility, color reflectance (chromaticity parameter a*), and natural gamma ray. Between ~60 and 85 mcd, the data seem to show no correlation except for a 62-72 mcd interval, in which GRAPE density and magnetic susceptibility correlate quite well. GRAPE density, magnetic susceptibility, and spectral reflectance appear to be directly correlated between 85 mcd and the base of the section.

Depth offset typically increases with depth, reflecting the fact that cumulative depth corrections are determined for each core. At Sites 1098 and 1099, the "growth" of the mcd scale with respect to the mbsf scale is of 6% and 1%, respectively (Figs. F38, F39).

Following construction of the composite depth section for Sites 1098 and 1099, two single-spliced records were built, avoiding where possible intervals with significant disturbance or distortion. They consist of Cores 178-1098C-1H, 178-1098A-2H, 178-1098C-2H, 178-1098A-3H, 178-1098B-3H, 178-1098A-4H, 178-1098B-4H, 178-1098A-5H, and 178-1098C-5H for Site 1098 and of all cores with the exception of the first 2.2 m in Core 178-1099B-1H for Site 1099 (Figs. F40, F41). The tie points for the splices are given in Table T31.