We built a meters composite depth (mcd) scale to Section 202-1241A-43X-2 (0.00-446.64 mcd) and a splice (as defined in "Composite Section" in the "Explanatory Notes" chapter) that documents complete recovery for the upper 303.14 mcd. The splice ranges from the top of Core 202-1241B-1H to the bottom of Section 202-1241A-29H-7 (see Tables T2, T3). All APC cores except for 202-1241A-30H through 202-1241A-34H can be correlated to the splice at Site 1241. One XCB core, 202-1241B-28X, is also included in the splice. Cores 202-1241A-30H through 202-1241A-43X and 202-1241B-29X through 202-1241B-32X were appended to the mcd depth scale. The splice was not continued beyond the base of Core 202-1241A-29H, due to a lack of a representative signal from these cores.
Above about 70 mcd, the mcd scale and the splice are based on the stratigraphic correlation of Oregon State University Fast Track magnetic susceptibility (OSUS-MS) measurements and multisensor track magnetic susceptibility (MST-MS) measurements collected at 5-cm intervals (Fig. F9; Tables T4, T5, T6). Below 70 mcd, gamma ray attenuation (GRA) bulk density was used for correlation (Fig. F10). Tie points (Table T3) were then used to construct representative spliced records for MST-MS, GRA bulk density, and where available, natural gamma radiation (NGR) data, (Fig. F11) and for color reflectance (L*, a*, and b*) data (Fig. F12).
We assumed that the uppermost sediment (the "mudline") in Core 202-1241B-1H was the sediment/water interface. A mudline was also recovered in Cores 202-1241A-1H and 202-1241C-1H. Core 202-1241B-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. F13) shows that the mcd scale is on average 13% longer than the mbsf scale. Given that the growth factor of 1.13 in the splice was relatively constant and that the splice represents ~68% of the drilled section at Site 1241, we appended the XCB cores from Hole 1241A (Cores 202-1241A-35X through 43X) by assuming a 13% (1.25 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.