Site 1221 extended to a total depth of 156.20 mbsf (Core 199-1221C-12X), but it was not possible to construct a complete composite depth scale for the site. We encountered severe flow-in problems in the uppermost ~20 mbsf, probably related to large heave motions of the ship. Below ~110 mbsf, commonly occurring chert layers prevented recovery. In the remaining intervals, the often soupy nature of the sediment (radiolarian ooze) resulted in MST data that were not suitable for correlation purposes, with the exception of the P/E boundary interval in the lowermost part of the recovered interval (see "Lithostratigraphy").
At Site 1221, magnetic susceptibility (MS) and color reflectance data were collected at 2-cm intervals and gamma ray attenuation (GRA) bulk density at 4-cm intervals. P-wave velocity data were collected at 2-cm intervals in those cores that were recovered by APC coring. Readings from the natural gamma ray (NGR) instrument showed only background radiation levels, apart from the P/E boundary interval in Core 199-1221D-4X. Over the Paleocene-Eocene interval, GRA bulk density and MS data were collected at 1-cm intervals. Disturbed intervals, as determined by visual inspection of split cores, are listed in Table T4. Data from these intervals were removed prior to correlation work. Table T5 lists the offsets that were applied to cores from each hole to create a partial composite depth record.
Cores from Site 1221 overlap and form a continuous sedimentary sequence only down to 19.5 mcd (base of Core 199-1221A-2H) (Table T6). Figure F9 shows the GRA bulk density, MS, and color reflectance data for the upper 20 mcd plotted on the resulting composite depth scale after removing disturbed intervals according to Table T4. Deeper in the section, it may be possible to correlate Cores 199-1221A-4H and 5H with Core 199-1221C-3H, using other records such as paleomagnetic intensity data. This correlation was not attempted aboard ship. In the composite framework for Site 1221, a depth shift of 0.5 m was applied to Cores 199-1221A-3H, 4H, 8H, and 9H in order to avoid overlap of data associated with the >100% recovery often encountered with APC coring. Between ~150.5 and 155 mcd (the P/E boundary), cores from Hole 1221B and 1221C contained correlative features and were depth shifted. However, for the remaining intervals there is no overlapping record from multiple cores. Furthermore, the lack of correlative features in the data collected from the soupy radiolarian ooze precluded the construction of a convincing correlation. Because of correlation problems and the lack of overlap between holes, the remaining data (primarily from Hole 1221A) were only appended in the composite depth framework according to the depth at which they were recovered.
The flow-in encountered in Core 199-1221A-1H resulted in an artificially longer section than what was actually cored. Thus, when features in the undisturbed lower portion of this core were correlated to equivalent sections in Holes 1221B and 1221C, the composite construction resulted in an upward (negative) shift in the mcd offset for Core 1H. Such a shift artificially places some sediment within this core above the sediment/water interface. However, this sediment is flow-in and does not represent in situ material. All undisturbed material in Core 1H remains below the sediment/water interface in the composite depth framework.