The 167-nmi transit between Sites 1227 and 1228 took 15.8 hr at an average speed of 10.6 kt. A positioning beacon was deployed at 1900 hr on 3 March 2002, ~75 m north of the Global Positioning System coordinates of Site 680, as reported on the first page of the Site 680 chapter in the Leg 112 Initial Reports volume (Shipboard Scientific Party, 1988b) and corroborated by the Ocean Drilling Program (ODP) Drilling Services Department operations report for Leg 112, in 273.6 m water depth (below rig floor). The vessel was moved to a position 50 m north of these coordinates to begin operations at Site 1228.
Continuous APC coring was initiated with Core 1H, which arrived on deck at 2155 hr on 3 March. Coring continued through Core 23P (0.0-200.9 mbsf) (recovery = 68%). Cores 1H through 8H (0.0-71.4 mbsf) had average recovery >100%, with the exception of Core 5H (recovery = 80%). Core 6H had a full core barrel but the liner was shattered, resulting in a severely disturbed core. Cores 9H through 23P (71.4-200.9 mbsf) were variably successful in terms of recovery, ranging from empty barrels (Core 17H), to poor-recovery intervals with soupy cores (Cores 11H, 12H, 15H; recovery = <20% for all), to cores with as much as 95% recovery of intact sediment. Core 10H did not advance and returned to the rig floor with the shear pins scored but not broken. We interpreted this to suggest that the bit was resting on a hard layer, obstructing penetration of the barrel. The core barrel was deployed again with the bit raised to 1 m off bottom so as to provide momentum for the piston core prior to penetration. The barrel still would not extend beyond the bit, indicating that there was an obstruction inside the throat of the bottom-hole assembly. An extended core barrel (XCB) was deployed to dislodge the obstruction, but the subsequent APC barrel (still identified as Core 10H) only pushed a short distance out of the bit and returned an intensely disturbed, low-recovery core. We drilled to the equivalent depth of a full piston stroke (9.5 m) and deployed Core 11H, which also misfired because of impact with a hard interval, and returned a core in much the same condition as the previous one, comprising a mixture of mud, sand, and gravel. While discussing our operational strategy, we deployed the Fugro Percussion Corer (FPC) (Core 13M) (109.4-110.4 mbsf; recovery = 40%), which returned a collapsed core barrel partially filled with gravel at ambient pressure.
Since our science objectives would be better served with a few meters of intact APC recovery than with any partial recovery the XCB might return, we chose to continue APC advancement, recovering what material we could and drilling down through multiple hard intervals. Recovery was sporadic (Cores 14H through 22H; 110.4-194.9 mbsf) (see Table T1), but in most cases we recovered sufficient intact core to meet our microbiological and geochemical objectives. Hole 1228A was terminated when the pressure coring sampler (PCS) cutting shoe dislodged and stuck in the bottom of the hole.
The DVTP was deployed at 42.9, 80.9, 137.9, and 194.9 mbsf, and the Davis-Villinger Temperature-Pressure Probe (DVTP-P) was deployed at 99.9 and 196.9 mbsf. We attempted twice to collect bottom-water samples with the Water Sampling Temperature Probe (WSTP) just above the mudline before beginning operations and after Core 1H, but both attempts suffered mechanical failure. A mudline temperature was measured with the Adara temperature tool before collecting Core 1H. A logging run with the triple combination (triple combo) tool string was completed in Hole 1228A. PFT was pumped continually during all coring operations at Site 1228 as part of our microbiological contamination testing protocol. In addition, fluorescent microspheres were deployed on Cores 2H, 5H, 11H, and 12H to help assess the potential of contamination in cores where heavy microbiological sampling was planned.
Since the location of the positioning beacon was ~20 m due north of the location of Hole 1228A and we were operating in shallow water, we were required to arrange our subsequent occupations relatively close to the beacon, while avoiding drilling into it. Offsets of 22 m north-northeast, 13 m north-northwest, 12 m northwest, and 20 m north were chosen for Holes 1228B, 1228C, 1228D, and 1228E, respectively.
Hole 1228B comprised six continuous APC cores (Cores 201-1228B-1H through 6H; 0.0-54.3 mbsf) (recovery = 107%). The upper five cores were sampled for shipboard high-resolution paleooceanography and paleomagnetism objectives. In addition, Core 201-1228B-6H was taken to fill gaps in the continuous geochemical and microbiological profile from Hole 1228A. The FPC was deployed at the bottom of Hole 1228B (Core 201-1228B-7M; 54.3-55.0 mbsf) and recovered 0.42 m of sediment.
The last three holes drilled at this site were cored for high-resolution shore-based sampling (Hole 1228D; Cores 201-1228D-1H through 3H [0.0-27.0 mbsf; recovery = 101%]) and shipboard geochemistry and microbiology (Hole 1228C; Core 201-1228C-1H; 0.0-7.5 mbsf [recovery = 100%], and Hole 1228E; Core 201-1228E-1H; 0.0-7.3 mbsf [recovery = 100%]). A WSTP sample was collected above the mudline in Hole 1228E. The FPC was deployed at the bottom of Hole 1228E (Core 201-1228E-2M; 7.3-8.3 mbsf). In addition to continuous PFT contamination monitoring, fluorescent microspheres were deployed on Core 201-1228E-1H. Operations at Site 1228 ended when the bit passed through the rig floor at 1200 hr on 6 March, and we began our short transit to Site 1229.