Multisensor track (MST) and spectral reflectance (L*) data collected from Holes 1168A, 1168B, and 1168C were used to determine depth offsets in the composite section. Magnetic susceptibility, gamma-ray attenuation (GRA) bulk density, and spectral reflectance measurements were the primary parameters used for core-to-core correlation at Site 1168. GRA bulk density and magnetic susceptibility data were collected at 2-cm intervals on all APC cores recovered from Holes 1168A, 1168B, and 1168C and at 2- to 4-cm intervals on XCB cores from Holes 1168A and 1168C. Spectral reflectance data were collected at 2-cm intervals on cores from Holes 1168A, 1168B, and 1168C. (see "Physical Properties" and "Lithostratigraphy" for details about MST and spectral reflectance data).
The data used to construct the composite section and determine core overlaps are presented on a composite depth scale in Figure F26. The depth offsets that comprise the composite section for Holes 1168A, 1168B, and 1168C are given in Table T14.
The composite data show that the APC cores from Site 1168 provide a continuous overlap to at least 120 m composite depth (mcd) (base of Core 189-1168B-12H). Below the APC section, most of the XCB cores from Hole 1168C could be tied into XCB cores from Hole 1168A and placed into a composite depth framework. Very few core gaps, however, could be bridged between the XCB cores from the two holes, and an XCB splice could not be constructed.
Stretching and compression of sedimentary features in aligned cores indicate distortion of the cored sequence. Because significant distortion occurred within individual cores on depth scales of <9 m, it was not possible to align every feature in the MST and color reflectance records accurately by simply adding a constant to the mbsf core depth. Core-scale changes will require postcruise processing to align smaller sedimentary features. Only after allowing variable adjustments of peaks within each core can an accurate estimate of core gaps be made.
Following construction of the composite depth section for Site 1168, a single spliced record was assembled for the aligned cores over the upper 120 mcd (base of Core 189-1168A-11H) primarily by using cores from Holes 1168A and 1168B. Intervals having significant disturbance or distortion were avoided. The Site 1168 splice (Table T15) can be used as a sampling guide to recover a single sedimentary sequence between 0 and 120 mcd.