Feb 29 - Swath fantasia
Date: 29th February 2004
Noon Position: lat 55 54.3' S; long 48 12.1' W
Distance Travelled since Immingham: 20541 Nautical Miles
Air temperature: 5.6°C
Sea temperature: 6.4°C
Swath fantasia - The Week In Brief
This week can be summed up in a few pictures, taken from the Monkey Island by Julia Sas:
Yes, while the ship steams up and down lines along a grid perpendicular to the direction of the swell, her occupants develop a way of walking which can best be described as drunken. As the ship rolls, stairs either become very easy or very difficult to climb: time it right and you can almost step up the whole flight without trying. Time it wrong however and it feels as if someone has tied lead weights to your ankles. Everything not tied down slides about the ship as she rolls, picking up momentum until they find their way onto the floor (where most of it stays in my case). It is important to remember not to overfill cups and bowls, and to hang onto any unfinished drinks. The more experienced sea farers have developed a way of swaying with the ship, keeping their dinner on their plates and somehow making it look effortless. The rest of us stagger about drunkenly, spill things often and expend huge amounts of energy just staying in one place.
As you have probably guessed, we are still swathing- all in the name of science!!!
There has also been a bit of dredging this week but the highlight were 2 birthday parties... Ian Raper and Tiffany Barry, both 21.
Ian, left, with Mike and Colin during fire hose training.
Tiffany with her birthday present.
Science Bit In The Middle
This week's science news is in two halves. Firstly, chief scientist Roy Livermore explains the purpose of our cruise, then Tiffany Barry and Julia Sas describe what they are planning to do with the results back in the UK .
Objectives of JR 77 and 78:.
The combined cruises have two main objectives. JR77 aims to acquire rock samples to constrain the history of the mantle beneath the Scotia Sea, from which the oceanic crust was derived by melting. JR78, by contrast, seeks to understand the role of the central Scotia Sea in the development of a deep connection between the Pacific and Atlantic oceans.
JR 77- Dredging:
Rock dredging is a crude, but effective, means of sampling the sea bed, in order to investigate the geological evolution of oceanic regions, and to date the ocean crust. A steel dredge is towed behind the ship at low speed, to dislodge pieces of rock, which are collected in the steel-link bag attached to the dredge. Rock samples are analysed to determine the amounts of major and trace elements present, while the ages are estimated from measurements of unstable isotopes, such as Potassium.
JR 78- Burdwood Survey:
We produced a detailed map of the bathymetry of an area in the northern Scotia Sea which includes a sediment-covered valley, fifteen miles wide and a hundred miles long, never previously mapped, except by satellites. If the seawater were removed, this region would appear as spectacular as the Great Rift Valley of East Africa, with walls a mile high, and rugged peaks flanking the valley floor.
Swath bathymetry map of the Burdwood survey area.
Last week we said we'd tell you more about what we're planning to do with these rocks (called basalts), once we get back to the UK. So here goes!
First we clean them so that what we are analysing is just basalt and not any of the manganese crud we told you about last week. Once this is done the rocks are crushed into fine powders and dissolved in very strong acid (he he he, mad scientist chortle) forming liquid solutions. By analysing such solutions we can determine the precise chemistry of the rocks. Every basalt will have its own particular chemical signature, but basalts from the same ridge will have certain chemical characteristics in common (a bit like common traits of individuals from the same family). The 'family characteristics' of basalts from a particular region allow us to determine such things as the depth of magma formation, and the nature of the area from where the magma first formed (called the source region). For example has the source region been melted before?
Julian Pearce washes down a basalt from the dredge.
But so what we hear you say, why should we be interested in such things?
One of the main questions we hope to be able to answer using the rocks collected from this trip, is what has happened to the Pacific Basin, through geological time. When we look at the larger 'family' groups of basalts from the Pacific, we see that they are chemically distinct from those basalt families that have erupted in the South Atlantic. This suggests that the source regions for the different 'families' are fundamentally different from one another. For this difference to occur, the source regions must have remained isolated for millions of years and not been able to 'intermingle'.
Now, we don't mean to worry you, but the Pacific basin is shrinking by 0.6 km2 per year. What we would like to know is what impact this will have on the magma source region beneath the Pacific. One idea is that Pacific-type source region will be squeezed through so-called 'gateways', one of which is situated here, between the South American and Antarctic plates (plates are the big slabs of crust the continents sit on). By studying the basalt chemistry of the Scotia Sea we will be able to detect any recent (geologically speaking!) interactions between Pacific and Atlantic magma source regions as this will have produced Pacific-Atlantic basalt 'hybrids'.
So there you have it- that's the reason why we are sat on this ship chugging around the Southern Ocean; and you thought we were just collecting rocks in a bucket chucked out the back!
The Engineering Department
This week, disguised as an engineer, I attempted to discover what engineers actually do...
Flawlessly disguised, the doctor goes undercover.
The engineering team is made up of four engineering officers, a deck engineer, 2 electrical technical officers (more on them another week) and 2 motormen. The chief engineer is the man who oversees the entire department, as well as being responsible for the safety of the ship.
The engine room's "Mr. Big", Duncan Anderson.
The three engineering officers are each responsible for the maintenance of particular parts of the engine room. Colin Smith, the 2nd engineer oversees the day-to-day running of the engine room, allocates jobs and looks after the main engines. Jim Stevenson, the 3rd engineer's specific roles are water treatment and fuel injection, while the 4th engineer Tom Elliott looks after the purifiers.
During the day (8am to 5pm), the engine room is a hive of activity. While the engines more or less run themselves, the engineers need to constantly keep an eye on the oil and fuel levels. Not only that but they also make both the electricity and the water we use every day, they dispose of the waste, process the sewage, monitor the air conditioning, maintain the plumbing and, most importantly, keep the accommodation heated. Phew.
After 5pm, the JCR operates an "unmanned machinery space" (UMS) policy, which means that there is no-one in the engine room unless a fault is detected by the alarm system. Each of the officers takes turns in doing "duty". This involves regular rounds of the engine spaces to ensure all is running smoothly, checking gauges and valves and answering the alarms if they sound. When they do, the duty man has 3 minutes to make it down to the engine room and switch the alarm off before the whole department is woken up. I'm told it's not much fun at 2am.
The three engineering officers:
The ship's main propulsion is electric, and is powered by four enormous diesel generators. Thus she is a sort of mobile power plant. From these generators, power is converted by recifiers for use by the propeller motor, which drives the ship. Power is also taken and, via several steps, converted into our domestic electricity, which powers the lights, the washing machine, the computers and whatever else we use. A further supply of power comes off the system and is kept as smooth as possible, to be used in the labs for the specialised and sensitive equipment the scientists use, and to power the bridge equipment.
The electric propulsion, the shape of the hull and the "resilient" engine mounts mean that the ship is smooth and remarkably quiet, so much so that it is sometimes difficult to tell whether we are moving or not.
Bruce and Angus are the engine room's handy-men, who specialise in fixing whatever is broken, painting whatever is unpainted, and creating whatever you want before you've even suggested it. They are also the men responsible for sorting out the rubbish (braver than me) and keeping the engine room greased, painted and clean.
Part of the engineering team but almost never seen in the engine room, is Doug "the deck". Doug is the deck engineer, responsible for the deck winches, cranes and the two small boats. He is always to be found with an eagle eye on the machinery whenever science is in progress or busily greasing and oiling anything that moves.
Doug the deck engineer greases the trawl winch in preparation for use next cruise.
There are two further members of the engineering department, the electrician Keith and the "sparky" or radio officer, Mike. However, I have yet to discover their worlds and so will leave that to another week.
A final thought and so Until Next week...
|The entire ship's crew sent outside to play in the "snow".||Lee and Ian playing nicely.|
The chief officer was clearly having withdrawal symptoms from the lack of snow, so had the deck department making it. Unfortunately it was a bit too soft for building snow men. For clues as to what the "snow" is made from, see above.
The spectacular sunset on Thursday. Click to enlarge.