JC010: Mud volcanoes and submarine canyons


Cruise diary

Day 12: Wednesday 23 May 2007
Position: Latitude 34º, Longitude 8º, Bearing 16º
Weather: Cloudy

Eduard writes:

"Yesterday was the hump day (halfway point). The days pass quickly! This morning, the van was quiet, and nobody was around the labs, so I took the opportunity to do my laundry and take some fresh air on the front deck. The ship was moving from the Darwin Mud volcano to another target travelling at 11 Knots! The sea was flat, this morning, and the ship didn’t roll a lot. However, after 11 days on board, nobody thinks about sea-sickness, here. Now we are over a geological feature called Western. Its depth is about 2800 meters. The scientists are investigating if this is a mud volcano or not. For this, they are doing bathymetry and some cores. If you want to see where exactly is the Western, just have a look to the Perspective View (below) that Andrey did especially for our diary. In this map, you can see the other targets of the cruise (in red).

When the cores came up this afternoon, the lab and the working deck were full of people again, cutting the cores and taking samples. Today we had an eight metre long core! The mud was the centre of attention: ‘Look at this part of the sediment, it has plenty of metals. And this part doesn’t contain any metal. Here, there is evidence of bacteria in the sediment. How do you know that? Because of this little black holes over there. Have you seen this worm I have found in the core? Look into the microscope. It is moving. Is still alive!’....more tomorrow!"

Gillian writes:

"We sailed to a new site today, Western. When sailing there has to be a bit of a lull in activity as nothing can go overboard so lots of tired scientists took the opportunity to have a bit of a lie in. On arrival the first thing to be done is the mapping of the seafloor. This requires lots of data which is taken using the echo sounders - 191 beams in fact - mounted on the bottom of the ship which give out sound at different frequencies. These are edmitted by the ship and then bounces back from the seabed, like an echo.  High frequency waves detect the general shape of the seabed and low frequency waves detect the amount of mud on the bottom of the seabed. These echo sounders can penetrate up to a depth of 11000m. Several computers are used to process this data and it is Paul’s job to coordinate all this.  The ship moves back and forth so slowly that it is about the same as walking pace, continually mapping. The scientists can then decide what to do with the site as they know roughly what is down there. This site seems not to be a mud volcano and so we are moving on to Carlos Ribeiro.

Eduard tried his hand at helping with the core sampling – he looked as though he really enjoyed it!"

Gill gets to grips with the physics of echosounding

Marina, Gill and Doug at work in the lab

Eduard turns his hand to core sampling

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