168 Preliminary Report

General Leg Information

The 10 sites during Leg 168 were occupied with 19 holes, four of which were cased into basement with reentry cones and "CORKed" and instrumented with thermistor strings and water samplers in the holes. They will be visited in the future by submersibles to download data and change the battery packages.

The sets of holes were close to each other and were completed in several steps. For example, while the cement on one casing string was curing, another hole was drilled deeper, or similar work was done in adjacent holes to reduce the time lost tripping pipe. Packer experiments and CORK placements were best accomplished during minimum ship heave conditions, so weather factors, too, determined when the work was done. It was an ongoing challenge to keep everyone informed of the ship's current operations. Some long transits in DP mode were made between sites when the slow transit time was still less than round trip pipe time.

San Francisco Port Call
After arriving by bus from the hotel, 16 June 1996, the technical staff and scientists waited several hours on the exposed dock for U.S. Customs to clear the ship and personnel.

Contributing to the delay was a problem with the visas of a few scientists. Their visas were not technically correct because of different entry requirements for those entering the U.S. by ship vs. by air.

Crossover between the teams went quickly and work with the technical representatives commenced. The laboratory microscopes were serviced by SERCO and repaired as necessary; a maintenance class was conducted for the photographers and their shore supervisor.

The FISON/ARL representative arrived late and then spent some of the time getting the instrument, which was used little on the previous leg, to operate normally. This was a routine service call.

The Costeck/Carlo Erba representative conducted a short training session for the chemistry specialists on instrument use and support procedures for the CNS instrument. Parts and instructions for bypassing the sulfur portion of the determination, a modification that speeds the results for carbon when there is no interest or little sulfur in the samples, were explained. There was no time to service the instrument to correct minor problems from previous legs.

The forward catwalk door sill was cut to deck level prior to port call to make it easier and safer to move the long and heavy original 2G cryogenic magnetometer unit out of the core lab and to bring its replacement into the lab. The exchange and installation were scheduled to take up to 5 days, but, in spite of a few harried trips to shore, the instrument was ready to test in 4 days. We did not notice initially that the HP Pentium PC provided to control the unit came without documentation or start-up disks.

Annual Performance Evaluations were conducted only for the sea going personnel during the port call. Bob Olivas, supervisor of the Technical and Logistics group, was present for 2 days to review written ship evaluations and to participate in the reviews, as directed by recent policy changes. This required a few of the off-going technical staff to stay over. They assisted in the loading of the two 40-ft containers of recovered cores. With a service call in progress the first day and the interview schedule, those few left to load the containers appreciated this help.

Public relations tours and science interviews were scheduled and conducted for VIPs on Monday and for the general public and educational groups on Tuesday. A tent and ODP displays were set up on the dock to inform and manage the crowd, while nearby dock workers unloaded and slung the reentry cones and other heavy equipment required to accomplish the objectives set for this leg. Visitors often walked right through the roped-off areas, impeding the movement of materials. In addition, union organization on the docks slowed down the movement of materials on and off the ship. The area in the core lab where the new cryogenic magnetometer was being installed was cordoned off. Crossover for the systems managers and JANUS representative and the microscope instruction sessions were disrupted by the numerous tours.

The tours were successfully conducted by scientists from the greater San Francisco Bay area who had sailed previously. An afternoon and evening reception was scheduled on Monday for the VIPs and scientists; the technical staff was invited and many were able to participate.

Under Way
TheJOIDES Resolution sailed at 9:03 a.m. on 20 June. Navigation tapes with depths and magnetic measurements were recorded on the track from outside the San Francisco's Golden Gate Bridge to the drill sites off the Washington state coast. No surveying of the area was necessary.

Several short (3 to 4 hr) transits were made between drill sites, and on two we took the opportunity to try one of the new solid-state six-channel streamers. An 80-in.3 water gun was deployed and fired. Difficulty with the SUN computers and a2d software resulted in little meaningful seismic information. A power lead in the streamer was thought to have failed, but further investigation hinted that the preamps had failed because of a possible short when the BNC connectors may have touched. The circuit apparently has critical ground requirements. The streamer was removed from the winch and returned to ODP for repair.

There was marginal success using the dGPS service in this area after being assured that this area was covered. A lengthy phone call with a CHANCE technical representative led the underway technician through a diagnostics routine. They determined that (1) one unit had a bad interface and needed to be returned for a replacement, (2) the antennas should be higher and have a less obstructed view of the horizon, and (3) the dGPS satellite is at 20° at this location, which is marginally low.

The last site, Site 1032, was drilled into basement and a suite of logs was generated. The ship was under way at 2400 on 15 August for port call at Victoria, British Columbia. Depths and magnetometer data were collected until the ship entered the Juan De Fuca Strait; navigation collection continued until the ship reached Victoria.

168 Laboratory Activities

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