Every other core at Site 1267 was recovered with a nonmagnetic core barrel until the first core barrel had to be drilled over (see "Operations") (Table T1). As at other sites, no obvious difference was noticed in the magnetic data between sediments recovered with the nonmagnetic barrel and those recovered with a standard core barrel. All APC cores in Holes 1267A and 1267B were successfully oriented with the Tensor tool with the exception of Cores 208-1267A-1H, 2H, 8H, and 25H and 208-1267B-1H, 2H, 3H, and 21H (see "Operations") (Table T1).
The archive halves of 69 cores from Holes 1267A and 1267B were measured in the pass-through magnetometer. Natural remanent magnetization (NRM) was measured on all cores. Most cores were demagnetized at 10 and 15 mT. As at other sites, a strong vertical overprint is largely removed by demagnetization to 10 mT.
The initial NRM (prior to demagnetization) of the sediments exhibits weaker intensity in the upper 100 mcd (on the order of 10–3 to 10–2 A/m) and stronger intensity below 100 mcd (on the order of 10–2 to 10–1 A/m) (Fig. F21). After demagnetization to 15 mT, intensities are typically on the order of 10–4 to 10–2 A/m, with the notable exception being the interval between 73 and 83 mcd, where intensities are on the order of 10–5 A/m.
As discussed in the Site 1266 chapter, the upper 100 mcd at Site 1267 also exhibits low magnetic intensity (Fig. F21), low to negative susceptibility (Fig. F22), and elevated values of depositional remanent magnetization normalized by susceptibility (nDRM) (Fig. F23). This was observed at all Leg 208 sites and, if no change in the average geomagnetic field intensity is assumed, could be interpreted as diagenetic alteration of magnetite.
The magnetostratigraphy of Site 1267 is similar to that of Site 1262 in that the mid- to upper Pliocene through the Pleistocene, as well as the Paleocene and uppermost Cretaceous, are well resolved (Fig. F24). Magnetostratigraphic age-depth tie points are given in Table T10. The placement of the top of Chron C2n (1.785 Ma) at ~17.5–18.0 mcd is confirmed by the shipboard cyclostratigraphy (see "Leg 208 Synthesis" in the "Leg 208 Summary" chapter) and agrees well with the bottom of nannofossil datum medium Gephyrocapsa spp. (1.69 Ma) at ~16.2–17.4 mcd (see Table T10; "Biostratigraphy"). The top of Chron C2An at ~31 mcd is also confirmed by the cyclostratigraphy.
Most of the Miocene and upper Oligocene are condensed or missing, but Chron C13n at the base of the Oligocene is well resolved (Fig. F24), as at all other sites. Chron C13n is constrained by the tops of nannofossil datums E. formosa and D. saipanensis. Most of the upper Eocene is lost in a hiatus, but we interpret the middle Eocene sequence from Chrons C20n through C22n. The lower Eocene is not well resolved, but the base of Chron C24n is tentatively identified in Hole 1267B at ~205 mcd. Confirmation of this awaits the analysis of discrete samples.
Below the P/E boundary, all of the polarity boundaries are identifiable in at least one of the two holes (Fig. F24). Whereas at other sites the inclination data from XCB cores are characterized by a high degree of scatter and are generally not interpretable, the data from Site 1267 XCB cores are excellent. This difference is attributed to the sediments at Site 1267 being relatively well lithified compared to those at the other sites. The lack of significant drilling-related deformation allows for the unambiguous determination of reversal boundaries for Chrons C26n through C31n.