Holes 1080A and 1080B were cored with the APC to a maximum depth of 50.3 mbsf at Site 1080. Measurements of magnetic susceptibility and GRAPE density were made on the MST, and color reflectance was measured with the Minolta spectrophotometer. All parameters were measured at 2-cm resolution at Hole 1080A and at 4-cm resolution at Hole 1080B. Graphic and quantitative alignment of stratigraphic features of the MST and color reflectance data were used to depth adjust adjacent cores to establish a meters composite depth (mcd) scale. Beginning from the core top, a constant is added to the mbsf scale to establish depth offsets for each core to assemble a single continuous composite section. For Site 1080, continuity of the composite section was documented to 44 mcd.
Construction of the composite section and determination of core gaps were constrained primarily by the magnetic susceptibility and, to a lesser extent, by using GRAPE density data. Color reflectance parameters chromaticity (b*), red/blue ratio [650 nm/450 nm], and lightness (L*) were used in support of the MST data. Data were filtered because gas voids and core expansion induced considerable noise into the physical properties measurements. Details of the filtering process are documented in the "Composite Section" section of the "Site 1075" chapter (this volume), with the exception that a seven-point Gaussian filter was used to smooth the color reflectance data, and a six-point Gaussian filter was applied to the GRAPE measurements.
The composite depth section shows excellent agreement between Holes 1080A and 1080B (Fig. 11). Depth offsets for individual cores relative to their meters below seafloor positions are given in Table 5. Intracore stretching and compression often lead to feature mismatches of the data, which are indicative of core distortion and cannot be resolved with a single depth adjustment per core. The splice at 34 mcd is based upon magnetic susceptibility; however, it is weakly supported by the other parameters and should be regarded with caution. Core expansion relative to the mbsf scale is ~8% (Fig. 12).
From the composite record, a continuous spliced record for Site 1080 was established using the aligned cores of Holes 1080A and 1080B (Fig. 13). The Site 1080 splice can be used as a sampling guide to recover a single sedimentary sequence from the top 44 mcd (42 mbsf). Tie points for the Site 1080 splice are given in Table 6.