Leg 172 Technical Report


Core Lab
High recovery and full implementation of the JANUS database and applications provided many challenges for the science and technical staff. The biggest nuisance was expanding gassy cores and split liners. The technical staff developed a new method for handling core expansion by cutting each section short (130 or 140 cm) and letting cores expand into capped liner patch. Splitting liners plagued the staff throughout the leg. No reason could be found for the problem and it is assumed that either the liners where made with inferior materials or that they deteriorated due to long term storage.

Sampling volume was light at each site resulting only in 18,384 samples being taken for 5688 meters of recovery. Most requests were deferred or partially deferred to the post-cruise sampling party. Only one hole from each site was sampled for "routine" shipboard analyses and investigator samples with a few exceptions. Preliminary isotope sampling took place at Hole 1062C; Cores 1 through 8 were sampled at 20-cm resolution for the various isotopic stage requests. All other preliminary isotopic sampling was conducted as pilot studies and at a much lower sampling resolution.

Downhole Measurements Lab
The APC/Adara temperature tool cutting shoe was used 10 times to measure in situ formation temperatures with a 90.0% success rate. The Water Sampling Temperature Probe (WSTP) pore water sampler was used three times to collect seafloor water samples for carbon isotope studies.

Electronic Service
The lab equipment operated satisfactorily during the leg. As always, the first two weeks were spent addressing minor problems that were discovered during start-up operation. A great deal of time was spent trouble shooting the 6-channel streamer installation in the Underway Geophysics lab. Both tensor tools operated erratically, though the electronics technician maintained one functioning tool by using parts from the other one.

Paleomagnetics Lab
New cryogenic magnetometer control software and the DTECH demagnetizer were tested and evaluated. 2G Enterprise's new version of the Long Core controlling software for the cryogenic magnetometer was given to ODP, and during the leg it was modified to comply with ODP's hardware configuration and file handling requirements. The new DTECH demagnetizer can demagnetize five or six samples at a time and has an auto-shutoff feature if the software detects any problems with the coil. It will probably see little service since the cryogenic magnetometer is much more automated and easier to use when doing large numbers of samples.

Physical Properties Lab
The MST was heavily used this leg and was the primary correlation tool. Halfway through the leg we discovered that the gamma-ray attenuation porosity estimator (GRAPE) had been miscalibrated. Because of the data table design in JANUS, we were able to correct the calibration constants and reapply them to the raw data. Other than that, the MST ran without any major problems.

Two new natural gamma-ray (NGR) sensors were brought on-board in Charleston and were installed. The index properties station now has a label scanner to input sample IDs. Magnetic susceptibility, GRAPE, P-wave velocity, and natural gamma-ray data from the MST can be graphically displayed using the new LabVIEW program called MSTV. The scientists can choose a site/hole to look at and can visually get a sense of the characteristics of the cores to determine where to do their sampling.

X-ray Lab
The X-ray diffraction (XRD) performed flawlessly throughout the cruise, requiring no repairs or adjustments and performing 235 analyses. The scientists used a new version of MacDiff to interpret the XRD data. This version includes several new features that significantly enhance the usefulness of the program. No samples were submitted for X-ray fluorescence (XRF) analysis.

The microscopes were serviced at the Charleston portcall.

Underway Geophysics Lab & Fantail
The Site Survey Panel requirement for surveying all sites kept us busier than usual. All surveys were conducted using the GI air gun loaned for testing from Seismic System Incorporated. The GI gun worked flawlessly and produced excellent records. Unfortunately, our testing of the six channel streamer was not so successful because of problems (still unresolved) with amplifier/filter electronics in the lab.

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