The paleomagnetic results from Site 1101 provide a magnetostratigraphy that correlates well with the GPTS from the onset of Subchron C2An.1n (3.040 Ma) at ~209.38 mcd upward through the Brunhes Chron (Table T3; Fig. F19). As at the other sites, exceptions occur in a few intervals where core deformation, dropstones, overprints, or low core recovery bias or obscure the paleomagnetic signal. Unlike the other sites, Site 1101 was cored in a single hole (Hole 1101A). Thus, coring gaps are not filled by core recovered from other holes. Several large coring gaps occur in the upper 60 m. The lack of redundant coring also makes it difficult to evaluate the origin of anomalous paleomagnetic directions. Owing to the sea state, in which large swells were common, coring disturbance and associated anomalous directions were more common and more extreme than at the other sites. As was the case at the other sites, we do not consider data from intervals that are highly disturbed by drilling.
Because only one working half of the core was available for sampling, we decided to focus our efforts on U-channel sampling. We collected only four discrete samples from Hole 1101A and the results from these all agree well with coeval split-core and U-channel results. More than 47,200 vector measurements were made on over 5900 intervals from U-channel samples from the Cores 178-1101A-1H through 15H, which were progressively AF demagnetized up to 80 mT (Table T9). Directions estimated from PCA of the demagnetization results confirm the shipboard results and interpretations, which were based on AF demagnetization of the split-core sections at 30 mT (Fig. F5). Overall, deviations between U-channel, split-core, and discrete sample results are negligible. Hence, the revised magnetostratigraphy is virtually unchanged from that completed during Leg 178 (see table T21 and associated discussion by the Shipboard Scientific Party, 1999c). The slight adjustments that we make here are based mainly on the higher resolution of the U-channel measurements, as indicated in Table T3. We also defined the boundaries for Subchron C1r.2r-1n (the Cobb Mountain Subchron) and Subchron C2r.1n (the Reunion Event), which were discussed by the Shipboard Scientific Party (1999c) but which were not included in their table T21. The identification of both of these subchrons is speculative given the short intervals over which they occur and the level of drilling disturbance that affects some intervals cored in Hole 1101A.
Using the revised magnetostratigraphy, we computed sedimentation rates between the identified reversals (Table T3; Fig. F20). Because the magnetostratigraphy agrees well with that of the Shipboard Scientific Party (1999c), the sedimentation rates are also nearly equivalent. The average sedimentation rate is 68.9 m/m.y. over the 217.7-m section cored, with little overall variation. Sedimentation rates were also nearly constant over the past 3 m.y. at Sites 1095 and 1096. The most notable changes at Site 1101 are the slower sedimentation rates during Chron C2n and the faster rates during Subchron C2An.1n, a pattern similar to that observed at Site 1096.