We built a meters composite depth (mcd) scale to Section 202-1240A-28H-3 (0.00-282.94 mcd) and a splice (as defined in "Composite Section" in the "Explanatory Notes" chapter) that documents complete recovery for the upper 278.36 mcd. The splice ranges from the top of Core 202-1240A-1H to the bottom of Section 202-1240A-27H-7 (Tables T2, T3). All APC cores except for 202-1239A-28H can be correlated to the splice at Site 1240.
The mcd scale and the splice are based primarily on the stratigraphic correlation of whole-core Oregon State University Fast Track magnetic susceptibility data (OSUS-MS) measurements collected at 5-cm intervals with a 10-s integration time (Fig. F8; Tables T4, T5, T6, T7). In one interval (~67-74 mcd), for the tie between Core 202-1240B-7H and 202-1240C-7H, gamma ray attenuation (GRA) bulk density was used to verify the correlation. Tie points (Table T3) were then used to construct representative spliced records for multisensor track magnetic susceptibility (MST-MS), GRA bulk density, and natural gamma radiation (NGR) data (Fig. F9) and color reflectance (L*, a*, and b*) data (Fig. F10).
We assumed that the uppermost sediment (the "mudline") in Core 202-1240C-1H was the sediment/water interface. A mudline was also recovered in Core 202-1240B-1H. Core 202-1240C-1H is the "anchor" in the composite depth scale. From this anchor we worked downhole, correlating records on a core-by-core basis.
A comparison of the mcd and mbsf depth scales (Fig. F11) shows that the mcd scale is on average 11% longer than the mbsf scale. Because the growth factor of 1.11 in the splice was relatively constant and the splice represents ~98% of the drilled section at Site 1240, we appended Core 202-1240A-28H by assuming an 11% (1.05 m) offset from the core above.
To facilitate the calculation of mass accumulation rates (MARs), we provide corrected meters composite depth (cmcd) in Table T2 and in Table T3 for depths within the splice.