After the hydrophones and thrusters were extended and the vessel settled on location, the PDR referenced to the DES indicated a water depth of 5031.4 mbrf. The nine-collar BHA employed at the previous sites was reassembled with a new C-7 four-cone rotary bit and a mechanical bit release. We initiated Hole 1161A at 2330 hr on 25 December and drilled to 116.0 mbsf before contacting basement. We deepened Hole 1161A by rotary coring from 116.0 to 145.3 mbsf (Cores 187-1161A-2R to 5R) before the hole had to be abandoned because of erratic high torque, rapid penetration, and poor recovery (15%). A tracer of fluorescent microspheres was deployed on Core 187-1161A-2R. The drill string cleared the seafloor at 1315 hr on 26 December, and we offset in dynamic positioning mode 200 m north.
At Hole 1161B, we washed through 158.5 m of sediment before contacting basement and retrieving a wash barrel, which recovered a few pieces of basalt. We advanced Hole 1161B by rotary coring from 158.5 to 167.0 mbsf (Cores 187-1161B-2R and 3R, 10% recovery) with the same poor drilling conditions we experienced in the first hole. Rather than attempting to start a third hole at this site, we decided that we had recovered sufficient material at this site to meet our primary shipboard objectives and to move to our next site. We deployed a second tracer of fluorescent microspheres on Core 187-1161B-2R. The drill bit cleared the seafloor at 0045 hr and the rotary table at 0915 hr on 27 December.
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