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SITE 1163

Transit to Site 1163
The west-northwest transit from Site 1162 to Site 1163 took about 10 hr at an average speed of 10.4 kt. At 2330 hr on 31 December, we slowed to 5 kt and ran a south-to-north SCS survey on a line 1 nmi west of and parallel to the precruise site survey track. Since the valley hosting the sediment-filled pond (our prospectus site) opened to the west, we hoped that we would find a more inviting drilling target along this line. When we could find no suitable sediment cover along this survey track, we steered a southeasterly heading, which carried us directly over the GPS coordinates of the prospectus site. Although the sediment pond is a small target at this location, we decided that the sediment thickness was sufficient to provide lateral support for the BHA. Although the duration of the survey was only 1.6 hr and covered 8 nmi, it had the distinction of lasting from one millennium to the next.

Hole 1163A
The PDR water depth referenced to the DES at this site is 4365.4 m. The nine-collar BHA employed at the other sites was reassembled, along with a previously used hard-formation C-7 four-cone rotary bit that was still in good condition. This bit was run with a mechanical bit release. We began Hole 1163A at 1030 on 1 January by washing through ~160 m of sediment below seafloor at an average penetration of 54 m/hr. When the driller noted a hard contact, we pulled the wash barrel (Core 187-1163A 1W, 0.0 to 161.0 mbsf). We advanced Hole 1163A by rotary coring 161.0-208.1 mbsf (Cores 187-1163A-2R to 11R) with generally good drilling conditions and 33% recovery. Microsphere tracers were deployed on Core 187-1163A-2R. We terminated operations at this site when we reached our depth objective of ~50 mbsf. The drill string cleared the seafloor at 2345 hr on 2 January and the rotary table at 0700 hr on 3 January.

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