A composite section was constructed for the upper 173 mcd of Site 1219 using MST and color reflectance data to determine depth offsets between cores in Holes 1219A and 1219B (Figs. F17, F18, F19). In Hole 1219A, MS and color reflectance data were collected at 2-cm intervals, and GRA bulk density at 4-cm intervals down to Core 199-1219A-16H, below which GRA bulk density data were acquired at 2-cm intervals. GRA bulk density data were collected at 2-cm intervals throughout Hole 1219B. In Hole 1219A, P-wave velocity data were collected at 2-cm intervals through Core 199-1219A-24H. No P-wave data were collected in the XCB portion of Hole 1219A. Minolta color reflectance data were collected on cores from both holes at 2-cm intervals. Readings from the natural gamma ray (NGR) instrument showed only background radiation levels below ~30 mbsf. This component from the MST assemblage was only run on Hole 1219A cores. Disturbed intervals, as determined by visual inspection of split cores, are listed in Table T8. Data from these intervals were removed prior to correlation work. Table T9 lists the offsets that were applied to cores from each hole to create a composite depth record.
Cores from Site 1219 overlap and form a continuous sedimentary sequence down to ~130 mcd (base of Core 199-1219B-11H), with the exception of two apparent gaps at ~90 mcd between the base of Core 199-1219A-9H and the top of Core 199-1219B-8H and at ~100 mcd between the base of Core 199-1219A-10H and the top of Core 199-1219B-9H. Between 130 and 173 mcd, cores were placed into a composite depth framework, but a continuous section could not be constructed over this interval because gaps were aligned and it was not always possible to establish the true stratigraphic position of the cores. For example, Cores 199-1219A-14H and 199-1219B-13H can be correlated to each other but not to cores above or below. Figures F17 and F18 show that in this interval between 142 and 151 mcd the position of these cores is not constrained with respect to Hole 1219A or other intervals above or below in either hole. The first core from Hole 1219B recovered sediment from 23 mbsf and below, so there is no spliced record available for the interval covered by Cores 199-1219A-1H through 3H. However, this interval of predominantly red clay was recovered in the site survey piston Core EW9709-12PC (Lyle, 2000). There is a problematic interval at the base of Core 199-1219A-6H and the top of Core 7H, where paleomagnetic data from both holes imply that these two cores overlap by nearly 2 m. Although visual inspection of the top of Core 199-1219A-7H does not show any evidence for disturbance, the MST data for the top three sections of this core are strikingly different than equivalent intervals in Hole 1219B.
Following construction of the composite depth section for Site 1219, a single quasi-continuous spliced record was assembled for the aligned cores down to ~173 mcd by patching across core gaps with data from Holes 1219A and 1219B (Table T10; Fig. F20). Intervals having significant disturbance or distortion (see Table T8) were avoided. The Site 1219 splice can be used as a sampling guide to recover a nearly continuous single sedimentary sequence between 0 and 173 mcd, although individual cores below 132 mcd are merely appended to the core above and the true stratigraphic position of these cores is unconstrained. When utilizing this splice as a sampling guide, it is advisable to overlap a few decimeters from different holes when sampling in order to accommodate anticipated ongoing development of the depth scale. Stretching and compression of sedimentary features in aligned cores indicates distortion of the cored sequence. Because much of the distortion occurs within individual cores on depth scales of <9 m, it was not possible to align every feature in the MST and color reflectance records. However, at crossover points along the splice (Table T10), care was taken to align highly identifiable features from cores from each hole. Postcruise work will establish a detailed correlation between holes by establishing a revised meters composite depth scale that allows differential stretching and squeezing within cores, following Hagelberg et al. (1992).
The MST data from Site 1219 bear a striking resemblance to those recovered from Site 1218 (see "Composite Depths" in the "Site 1218" chapter) from the uppermost Eocene-lowest Miocene interval. The excellent match between the two sites made it possible to align both records on a common (Site 1218 mcd) depth scale (Fig. F21). The two records show such correlation (down to the submeter scale) that a priori prediction of biostratigraphic zones and paleomagnetic reversals was possible at Site 1219. The correlation between the mcd scales from both sites will allow the postcruise evaluation of missing intervals from either site as well as the determination of core gaps in intervals from Site 1219 where no continuous overlap was achieved. The mapping from Site 1219 mcd to Site 1218 mcd (see bottom of Fig. F21) results in relative sedimentation rates at Site 1218 that are ~16% higher than Site 1219 over the Oligocene interval.
Downhole logging data were collected from Hole 1219A (see "Downhole Measurements"), which will allow a detailed postcruise core to log correlation and integration. The detailed match between Site 1218 and 1219, established from the MST data, will also facilitate a detailed log-to-log correlation from both sites.