Based on satellite images from the National Ice Center (Washington, D.C.) and reports received from the Hakurei-Maru, a research vessel that had been operating in the area a week before our approach, it was unlikely that the primary shelf site (PBS-2A) would be ice free. Our plan was to locate the shelf site as far to the west as the ice would allow by heading for proposed site PBS-9A and to proceed from there to the west toward proposed sites PBS-8A, PBS-7A, and possibly PBS-1A. During the transit into Prydz Bay, with ice floes to either side of the vessel, it became clear that it was unlikely that sites farther to the west would be free enough of ice for drilling. The decision was therefore made to drill at site PBS-9A. Unfortunately, we discovered that a large iceberg was located directly over the selected drill site. As we were rapidly approaching our survey waypoint, we decided to move the site 3 nmi to the northwest along seismic line BMR 33-23P3. Permission for the new drilling location, named PBS-9B, was requested by telephone and fax and granted during approach to the site. A site survey was attempted but ended before reaching the drill site because one water gun froze up and the other water gun broke an air hose. There was not enough time to fix these problems before nightfall, when the ship had to be on location because of numerous nearby icebergs and ice floes.
Hole 1166A was spudded with the rotary core barrel (RCB) at 0745 hr on 16 February. Continuous RCB coring proceeded to a depth of 199.5 mbsf (Tables T1, T2), when the passage of a large low-pressure system led to a deterioration of weather conditions and sea state. Drilling operations were halted at 2130 hr on 17 February because shallow-water operating guidelines went into effect, thereby limiting our operating environment to <2 m heave and wind gusts of <40 kt. When an iceberg came within 0.6 nmi of the ship, the decision was made to pull the drill string clear of the seafloor. A free-fall funnel could not be deployed because of the hard seafloor. The drill string was raised to a safe height, and the vessel was offset 1.0 nmi to avoid the iceberg that moved directly over the vacated drill site. After the iceberg and the low-pressure cell moved across Site 1166, conditions improved enough by 0630 hr on 19 February to deploy the subsea camera and reenter Hole 1166A. The reentry operation took only 13 min and was completed without the aid of a guide cone or funnel. A total of 38 hr was lost because of the storm.
The reentry showed that the seafloor was 6.7 m shallower than identified by the driller's blind tag with the bit at the start of the hole. Observations with the television camera showed a seafloor depth of 468.7 meters below sea level (mbsl). Corrections to the database were not performed (i.e., adding 6.7 m to all subsurface depths). Continuous RCB coring resumed and continued to a depth of 381.3 mbsf. Overall recovery for the hole was 18.6% (Tables T1, T2).
In preparation for logging, the bit was released, the hole was displaced with sepiolite logging mud, and the drill string was tripped to the logging depth of 48.0 mbsf. The hole was logged with a full suite of sensors (triple combo, FMS suite, and GHMT) from 33.0 to 377.3 mbsf. All logging runs were successful. By 0745 hr on 21 February, the logging sheaves had been rigged down and the wireline logging program was completed.
The hole was abandoned with a 21.5-bbl plug of cement, and the drill pipe was pulled clear of the seafloor and tripped back to the ship. At 1600 hr on 21 February, the rotary table was clear, ending Hole 1166A.
Hole 1166B was planned to gain LWD logs from the upper section of the hole that was not logged by wireline tools and to get downhole drilling parameters (e.g., weight on bit) in real time by measurement while drilling (MWD).
The drill string was tripped to bottom, and Hole 1166B was spudded at 0020 hr on 22 February. The seafloor depth was determined to be 482.5 mbsf, and the first hard layer was contacted at 485 mbsf. Drilling proceeded very slowly for the first 25 m. Very little weight could be put on the drill string until at least the measurement- and logging-while-drilling (LWD/MWD) tools were buried beneath the seafloor. The hole was terminated at a depth of 40.0 m because the primary objectives of running LWD/MWD had been met and time restraints disallowed further logging.
The hole was displaced with heavy mud, and the drill pipe was pulled clear of the seafloor by 1020 hr. The beacon was released and recovered aboard at 1050 hr. The pipe was back aboard ship and the LWD/MWD tools were rigged down by 1330 hr on 22 February, and the JOIDES Resolution was under way for Site 1167.