Multisensor track (MST) and spectral reflectance (L*) data collected from Holes 1212A and 1212B 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. GRA bulk density and magnetic susceptibility data were collected at 3-cm intervals and spectral reflectance data were collected at 2.5-cm intervals on all cores (see "MST Measurements" in "Physical Properties" and "Lithostratigraphy" in the "Explanatory Notes" chapter for details about MST and spectral reflectance data).
The data used to construct the composite section and determine core overlaps are presented in a composite depth scale in Figure F12. The depth offsets that comprise the composite section for Holes 1212A and 1212B are given in Table T6. Units for the composite depth scale are meters composite depth.
The composite data show that the APC cores from Site 1212 provide a more or less continuous overlap to at least 115 mcd (K/T boundary; ~109 mcd in Core 198-1212A-12H). Core 198-1212B-2H was tentatively appended to Core 1H (Fig. F13; Table T7), as there was no overlapping interval recovered in Hole 1212A. As a result, minor offsets between holes have been found within the underlying ~40 mbsf. This led to inadequate overlapping of accompanying cores (Fig. F13; e.g., the base of Core 198-1212B-3H was tied to the top of Core 198-1212B-4H, the base of Core 198-1212B-4H was tied to top of Core 198-1212B-5H, the base of Core 198-1212A-2H was tied to the top of Core 198-1212B-3H, the base of Core 198-1212A-3H was tied to the top of Core 198-1212A-4H, and the base of Core 198-1212A-5H was tied to the top of Core 198-1212A-6H; see Table T7). There may also be a gap between Cores 198-1212B-11H and 12H (Core 198-1212B-12H was appended to Core 198-1212B-11H; see Table T7), as no overlapping interval was recovered in Hole 1212A.
Below the uppermost Maastrichtian, most of the cores from Holes 1212A and 1212B could not be correlated and placed into a composite depth framework because of low signal amplitude. Expansion of sedimentary features in one hole relative to coeval cores in the other hole indicate distortion of the cored sequence. Because some distortion occurred within individual cores on depth scales of <9 m, it was not possible to accurately align every feature in the MST and color reflectance records by simply adding a constant to the mbsf core depth.
Following construction of the composite depth section for Site 1212, a single spliced record was assembled for the aligned cores over the upper 115 mcd using cores from both holes. Intervals having significant disturbance or distortion were avoided. The PETM interval in the composite was taken from Core 198-1212B-9H.