Week 4

Three monitors in the Operations office displaying drill floor (top), drill string just above the re-entry cone(middle) and “Tru-Vu” drill rig instrumentation screen (bottom).

A successful re-entry showing the drill string passing through a cloud  of drilling mud – a “Hole-in-one!"

Joerg Gelmacher, Igneous Petrologist (Germany) choosing a sample.

Masako Tominaga, Physical Properties Specialist (US) discussing an interesting sample with Eugenio “Andres” Veloso Espinosa, Paleomagnetist (Japan).

While sitting at my desk in the Operations office, I can glance up at the three TV monitors to see what is going on all over the ship. There are cameras installed in strategic locations. Video displays from the cameras can be watched around the clock, each one on a different channel. In the Operations office, the middle screen has a view from the subsea camera. The top screen shows the drill rig floor with the wire line counter (a prominently displayed number that indicates the depth of the subsea camera, or the core barrel when retrieving a core). The bottom screen displays the drill rig instrumentation “Tru-Vu” screen. Tru-Vu allows the driller to keep an eye on drilling parameters such as rate-of-flow, torque, pump pressures, etc. Today, the subsea camera was deployed to watch the re-entry into the hole after the 4th bit change. Watching the view from the subsea camera on its descent to the seafloor and its return to the surface, I can see an incredible variety of sea life. At a depth of about 600 meters there is a school of squid and what I am told are jellyfish. Occasionally a fish swims into view. Usually the fish swim so quickly that you can’t tell what they are, but sometimes they are slow enough to get a good look. There is a lot more aquatic life than I thought there would be at 3600 m. Before re-entering the hole, a bottom water and temperature sample is taken with the WSTP (Water Sampling Temperature Probe) tool at approximately 2 meters above the sea floor.  Today the working halves of all cores drilled so far are set up for a sampling party. This is where samples of rock are taken for use in shorebased studies. The working halves are placed throughout the core lab, covering all available space. There are cores everywhere! Re-entry into Hole 1256D was accomplished at approximately 1015. The bit moved over the mouth of the cone and straight through a cloud of drilling mud without a single hesitation. It looked like the bit on a drill press, unable to miss because it was locked in place. While the drilling crew resumed the drilling process, the sampling party (see 28 July 2005 for more details) began. The scientists made their selections over the course of several hours, so there were never too many people in the Core Lab at any one time. The process was well organized and went very smoothly.

Just a few of the sections of core ready for the sampling party.

A fatigue crack just above the bit in the bit sub.

Joerg Geldmacher, Igneous Petrologist (Germany) and Carole Cordier (France), discuss the site report for the  igneous petrology group while Akram Belghoul, Logging Trainee (France) and Laura Galli, Metamorphic Petrologist (Italy) catch a moment in the sun. **

Joerg Geldmacher, Igneous Petrologist (Germany) always has a smile for the camera.

During the last two cores, the observant TransOcean drilling crew noticed an abnormal drop in the drill pump pressure when the bit was picked up off of the bottom. It was decided to “trip” (pull) the pipe and inspect it in hopes of determining the cause. The reason for the pressure drop became apparent when the bit made it to the rig floor. There was a structural fatigue crack almost all the way around the bit sub (about 2 1/2 feet/75 cm above the bit). Had the crack made it all the way around, the bit would have been left in the hole. “Fishing” it out with a specially made tool would have been a difficult maneuver. Thanks to the expertise and intuition of the TransOcean crew, a great deal of expedition time and expense was saved.

A new bit and bit sub were installed, and down they went. There was time to get caught up with other activities (my journal, project, and pictures) during the pipe trip.

Wow, it was sunny and warm today, ALL DAY!  Anyone who could find a few spare minutes took advantage of the weather and headed for the Steel Beach (the steel deck used for sunning).

 

At this point in the cruise everyone has fallen into seemingly choreographed routines. From the Catermar staff (who cook our excellent meals, wash our clothes and clean our rooms), to the TransOcean crew (the ship’s marine, electrical and drilling crew). It was good to return to the business of bringing up cores. Five cores were recovered. All lab groups stayed on-task keeping the well-oiled machine going.

“Double Hump Day.”

A photograph of a 5 mm portion of a thin section of a basalt with a fine-grained ground mass with plagiocase (long) and clinopyroxene (colored) crystals.

Carole Cordier, Igneous Petrologist (France) describing a thin section. *

Today is Hump Day (the half way point, it’s down hill to the end of the cruise). More precisely, it is “Double Hump Day”. Not only it is hump day for the cruise, it is hump day for the week.

I will start working on core descriptions today by helping with the Visual Core Description (VCD) sheets.  There are three groups of scientists who describe the core:  igneous petrologists, metamorphic petrologists and structural geologists. I will work with the igneous group first, followed by the metamorphic petrologists (also known as the alteration specialists). Finally, I will join the structural petrologists as they describe the cores. Working with Takashi Sano, Igneous Petrologist (Japan); Carole Cordier, Igneous Petrologist (France); Sedelia “Sid” Rodriguez Durand, Igneous Petrologist (US); and Joerg Geldmacher, Igneous Petrologist (Germany) in the Core Lab, we reviewed the cores that had been recovered today before moving on to the thin section lab. Constant discussion and collaboration between them is essential for the identification of minerals. This group of scientists gets along well and works together like they’ve known each other their whole lives. They readily ask advice and discuss what they are working on with each other. When asked, there is no hesitation to drop what they are doing and go to the aid of their colleague.

Takashi Sano, Igneous Petrologist (Japan) and Joerg Geldmacher, Igneous Petrologist (Germany) describing a section of core.

Being in the microscope lab with the igneous petrologists yesterday helped prepare me for working with them today on core descriptions. At the description table we looked at each piece of core to determine color, grain size, unit boundaries (areas where differences in composition, texture or structure can be seen), contacts (boundaries where lava forms a new layer of rock on pre-existing rock) and chilled margins (where hot lava cools against previously existing rock). When opinions differed among the igneous petrologists, the discussions that ensued between them were a lively, as well as a valuable lesson in the scientific process. As they discussed their reasoning you could see the description process in action. They told me to never be afraid to jump in with a comment because everyone’s opinion helped. Often, a passerby would be asked his or her thoughts on a piece of core. There was no rivalry at all, just teamwork.