The short transit (28 nmi) to Site 1212 was completed in 3.2 hr at an average speed of 8.8 kt. At 0955 hr on 29 September 2001, the ship was switched over to dynamic positioning mode, initiating operations at Site 1212.
An APC/extended core barrel (XCB) bottom-hole assembly (BHA) was run to 2689.0 meters below rig floor (mbrf), and Hole 1212A was spudded with the APC at 1540 hr on 29 September. The mudline core recovered 4.96 m of sediment, indicating a seafloor depth of 2693.6 mbrf, or 2682.5 meters below sea level (mbsl). APC coring advanced the hole to 101.6 mbsf with 115.1% recovery (Table T1). Cores 4H through 13H were oriented. After an incomplete stroke on Core 13H, we terminated coring in Hole 1212A. The drill string was recovered to the seafloor at 0255 hr on 30 September, ending operations at Hole 1212A.
The ship was offset 15 m to the north and the bit was positioned at a depth of 2689.0 mbrf. The same bit position was used in an attempt to keep critical intervals from falling at core breaks. Hole 1212B was spudded at 0345 hr on 30 September, recovering 6.74 m and establishing a seafloor depth of 2691.8 mbrf, or 2680.6 mbsl. Continuous APC coring progressed to 101.2 mbsf. Cores 4H through 12H were oriented. After an incomplete stroke on Core 12H, we adopted a strategy of deploying the XCB center bit to drill through chert layers, followed by redeployment of the APC. Ten deployments of the XCB center bit were required, including three to penetrate a layer at ~136 mbsf, drilling through 14.8 m to obtain 13 additional APC cores. Total APC recovery for Hole 1212B was 93.6%. Because of the increasing frequency of chert layers and diminishing core recovery on the last three APC cores, we terminated coring at Hole 1212B at 207.6 mbsf. The drill string was retrieved, clearing the rig floor at 2330 hr on 1 October, which concluded operations at Site 1212.