Sites 1228 and 1229 are 9 nmi apart, so the transit between them only required an hour, and a positioning beacon was deployed at 1330 hr on 6 March 2002 at the coordinates recorded in the Leg 112 Initial Reports volume (Shipboard Scientific Party, 1988) and verified by the Ocean Drilling Program (ODP) Drilling Services Department operations report for Leg 112. Coring operations at Site 1229 are detailed in Table T1.
Our first operation at Site 1229 was deployment of the water sampling temperature probe (WSTP) to collect a bottom-water sample. A short in the electronics prevented the tool from functioning properly, and an in-line capacitor was installed in the tool to prevent similar failures in future deployments. Continuous advanced hydraulic piston coring (APC) through Core 4H (0.0-33.4 mbsf) returned 98% recovery. The signal from a DVTP temperature measurement at this depth appears noisy, but a severe current was rattling the drill pipe and the formation may have been unsuitable to sufficiently seal the tool in the sediment. APC coring continued to 58.9 mbsf (Cores 5H through 7H), where we intended to make another DVTP measurement, but poor recovery in the last two cored intervals above this depth prompted us to delay this effort. Recovery improved on the next two cores (Cores 9H and 10H) (58.9-77.9 mbsf; recovery = 98%), so the DVTP and the DVTP-P were deployed after Cores 9H and 10H, respectively.
As we experienced significant overpull while extracting Cores 9H and 10H, mud pills were pumped after each subsequent core to clean the hole and we began operating in a drill-over mode. High recovery continued through Core 12H (77.9-107.9 mbsf; recovery = 96%), followed by a third DVTP temperature measurement. Cores 13H and 14H (107.9-126.9 mbsf) had somewhat poorer results (average recovery = 75%). The APC-M tool was run continuously from Core 201-1229-2H through 13H. The next three cores (Cores 15H through 17H; 126.9-155.4 mbsf) returned only severely disturbed cores composed of gravel and mud. Based on this result, we aborted a planned deployment of the FPC tool. Because our goal was improved recovery in the lower part of the section compared to Leg 112, we drilled through this interval and attempted two APC barrels (Cores 18H and 19H; 155.4-174.4 mbsf), which returned an interval satisfactory for geochemical and microbiological sampling. The DVTP was deployed after Core 18H at 164.9 mbsf. Core 20M was a deployment of the FPC tool. Cores 21H and 22H took us near our depth objective (194.4 mbsf), but we again experienced poor and disturbed recovery in muddy gravel, so we opted not to perform planned pressure and temperature measurements at this interval and aborted an additional run of the FPC tool as well. Operations at Hole 1229A concluded with logging the entire cored interval using the triple combination (triple combo) tool string.
Perfluorocarbon tracer (PFT) was pumped continuously in all holes at Site 1229 as part of our contamination monitoring protocol. In addition, fluorescent microspheres were deployed on Cores 2H, 3H, 4H, 6H, 9H, 11H, 16H, 17H, 19H, and 22H. Elevated hydrogen sulfide (as high as 50 ppm) was measured with handheld detectors at the rig floor and on the catwalk for the upper part of the cored interval, although hydrogen sulfide was undetectable below 30 mbsf. Nevertheless, alert precautions were maintained throughout coring at this site.
Using the dynamic positioning system, we offset 5 m north from Hole 1229A to initiate Hole 1229B. We were restricted in offset distance and direction in order to maintain a reasonably clean signal from the positioning beacon in shallow water. The upper three cores from this hole (Cores 1H through 3H) (0.0-24.4 mbsf; recovery = 102%) were dedicated to shore-based paleoceanography studies, so the cores were not split and the end caps were sealed with tape rather than acetone. Operations at Hole 1229B concluded with a deployment of the FPC tool at 24.4 mbsf. During this deployment the tool was damaged beyond our capacity to repair at sea, so no more deployments were planned.
After an offset of 20 m west from Hole 1229B, operations began in Hole 1229C with a WSTP deployment, which returned a bottom-water sample. High-resolution sampling of the upper few meters of the sediment column was one of our objectives for this hole, so when Core 201-1229C-1H returned with the upper end of the core liner collapsed and the mudline disturbed, we terminated the hole. A second mudline attempt, offset 5 m west-northwest (Core 201-1229D-1H) (0.0-6.8 mbsf; recovery = 100%), was suitable for our sampling plan and initiated Hole 1229D.
Continuous APC coring continued through Core 201-1229D-9H (to 77.8 mbsf), averaging 81% recovery. The core liner on Core 201-1229D-8H was shattered, resulting in a severely disturbed core. A PCS deployment on Core 201-1229D-10P returned under hydrostatic pressure and contained a mixture of air and methane. An interval between 85 and 90 mbsf that fell at the junction between cored intervals in Hole 1229A was determined by geochemical analysis to be of particular interest, so we asked the drilling crew to optimize our chances of complete recovery of this interval in Hole 1229D. Core 201-1229D-11H was shot from 5 m above the bottom of the hole, thus advancing only 4.5 m to 84.3 mbsf. The subsequent Core 201-1229D-12H bridged the interval of interest, and although the core was partially disturbed, sufficient intact material was recovered to sample for geochemistry and microbiology. Cores 201-1229D-13H through 15H (0.0-115.8 mbsf; recovery = 72%) completed operations in Hole 1229D.
For our final penetration at Site 1229, we offset 20 m west of Hole 1229D. Continuous APC coring from Core 1H through 13H (0.0-121.5 mbsf; recovery = 82%) was interrupted only by a short deployment of the DVTP at 83.5 mbsf to augment our thermal profile at this site. Operations at Site 1229 concluded when the bit passed through the rig floor at 0700 hr on 10 March, and we began our transit to Site 1230.