Six-Day Log

Storegga Slide Coring Cruise

Written by Michele Hatton
Educator & Florida State undergraduate geology student

Wednesday, September 1 – At Sea

I took a turn in the lab today. Learned how to squeeze pore water out of mud. (Note: you don’t use cheesecloth.) However, the longer I stayed in the lab, the lower the ceiling dropped, or so it seemed. So, I had to return outside to the deck on occasion, for a breath of fresher air (occasionally mixed with diesel fumes, depending upon my position on the deck).

Our task in the laboratory is to collect 30 milliliters of fluid from the base of each meter of core. One person saws off a five-centimeter, intact chunk from the base of the cylinder of core sediment, and then those of us in the role of lab tech label, log, and photograph the chunk. After the photo-op, we carefully extract smaller samples that will be examined later for water content, grain size, paleontology, and isotopic composition.

Next, we scoop out most of what is left. This is fun. The stuff looks and feels like silky smooth chocolate icing. We place the scoop into a heavy, cylindrical, Reeburgh-style squeezer body, which is attached to the squeezer apparatus.

The squeezer body is then capped with filter paper, o-rings, latex sheets, and a heavy top to create an airtight, closed-system chamber, from which fluids and gases cannot escape. The sample is pressurized to 35 psi, which pushes fluid and gases from around the mud grains and into a collection syringe attached at the bottom. If the sediment is very soupy, the job is over in 15 minutes. If the sample is very stiff, it can take up to 12 hours. If the sample is really stubborn, it must face the stronger Manheim-type squeezer.

We were instructed to handle these specimens with utmost care to avoid even that one micromole spec of contamination. In fact, prior to being re-used, some of the equipment is routinely soaked for hours in nanopure water to remove any trace of gas absorbed by the plastic. So, today I very carefully prepared our samples for the squeeze machine. Since our primary objective on this cruise is to collect and characterize pore fluids and gases from deep-sea sediment, this preliminary lab work done on-board is pivotal to the goal.

After the pore water is collected from the samples the full syringes then go up to Dr. Ussler’s infamous van. I discovered today why this van was the center of so much talk. It is a mobile pore water laboratory, custom-made and decked out with several state-of-the-art-chromatographs that analyze chloride, sulfate, and methane concentrations right there, on board. It was transported to Bergen all the way from California and now sits on the uppermost deck with its large picture window facing out to the sea, a view to die for. Dr. Ussler clearly must have had inspiration as well as science in mind when he designed the thing.

In the galley tonight, we moved the little tables together to make one big table, which we all shared. Dinner was a choice of salmon or steak, asparagus, homemade olive bread, and apple pie. I have come to see that dinnertime is as important as pore water. It reinforces camaraderie. What moves me the most though are the young women on our team. They pursue a traditionally male-dominated field without blinking an eye. Not only are they brilliant geologists, but they are aware, sensitive, and multifarious human beings. I’m glad to see this generation of gals reap the benefits from the toil of the previous generation.