‘Core is on the floor’ is the what we hear through the intercom system on the ship, every time when a new piece of sediment floor comes up from the seafloor. What happens after the announcement is a highly streamlined sequence of steps. First the IODP technicians go out on the catwalk (see picture), where they put the core on racks, label it, and cut it in pieces.
The catwalk is where the core first arrives. Normally it is an open space, but since it is quite cold down here off Antarctica, they put up a nice little wall to give the technicians some shelter from the cold wind.
From there it goes inside the ship and is left alone for some hours to equilibrate. Then it gets put through a series of so-called track systems, where the physical properties of the sediment are measured. After this, the core is split into two halves – a working half and an archive half. The archive half goes to the sedimentologists, who take pictures of it and describe what type of sediment we found, what colour it has, and what the likely depositional environment was. The working half is used by the palaeomagnetists to measure the magnetic field, which helps us to figure out the age of the core. A complimentary way to find out about the age is to look at the palaeontology in the core (diatoms, radiolarian, dynoflagellates, foraminifera, nannofossil). This is done by another group of people on the ship. They prepare slides and then look at them through the microscope. Finally we, the geochemists, take a sample for determining the amount of carbonate in the core, as well as the elemental composition of the sediment. All this sampling happens on the ‘sampling table’ (see picture). Afterwards the cores are wrapped and stored away.
James Bendle (organic geochemist, Glasgow) during his sampling shift, taking samples for all other scientists from the core on the sampling table (photo credit: Christina Riesselmann).
We are currently drilling our last Site for this expedition. We are recovering a very nice looking record of the more recent past of Antarctica (i.e., the past few million years). Our last attempt to go to the shelf failed yesterday, as the ice is moving in for the winter. Hence the only thing left to do is to drill a bit further offshore. Soon we will start wrapping up all our analyses, finalize the reports we have to write, and pack things away for our return to shore. It has been a long cruise, but I could still stay out for longer. It is simply amazing how much cool science you can get done on the Joides Resolution with all its analytical capabilities, the drilling crew, the IODP technician, and thirty scientist, focusing on one single goal: to make this expedition a scientific success. And we succeeded big time!
Part FIVE of the weekly updates from the JOIDES Resolution, sailing for the Antarctic coast of Wilkes Land between January and March 2010. Our mission: exploring the climate history of Antarctica. This week features sedimentologist Rob Dunbar from Stanford University. Enjoy!
Below you can see a picture of our ship track on the Antarctic shelf over the past few days. The curly line is the result of quite difficult ice conditions with huge icebergs and some sea ice in the area where our targeted drill sites are. Earlier this week we had to sit out a storm, caused by a significant low pressure system going through the area. This was done away from the shelf, where there is only very little ice, making it a safer place to be in rough seas. On Tuesday we started the journey back to the continental shelf, to drill some more material that tells us about the transition from the Greenhouse world into the icehouse world. On the shelf this transition can be found in only a few hundred meters depth below the seafloor (ice advances and retreats over the past ~34 million years have scraped off the younger deposits from the shallow ocean floor). In contrast, at the deep water site where we drilled first, the Greenhouse-icehouse transition was down at ~900m below the seafloor.
Ship's track over the last few days.
Our ship’s track is such a wiggly line, as we had to find our way through a lot of ice. The captain and the ship’s crew are doing a fantastic job, in trying to get us back on site, but drilling on the shelf of Antarctica is not a trivial task. We are lucky that we recovered some amazing cores already, and we still hope to get some more. However, the weather window (it is summer down here at the moment) will close eventually, and most of our targeted drill sites will be covered with ice for the winter. But we have about two weeks of science time left before we will return to Hobart (Tasmania). Keep your fingers crossed that we not only get more wonderful sunny days with gorgeous icebergs, but that the icebergs stay far enough away from us so that we can continue our scientific mission and get more spectacular core material!
My colleagues Masao Iwai (Japan, paleontologist) and Masako Yamane (Japan, sedimentologist) enjoy the nice weather today. In the background you can see icebergs, which are grounded on the continental shelf, as well as the Antarctic ice sheet.
I have been writing a lot about the excitement of being at sea. This post will be dedicated to giving you some impression on how life aboard the ship (the Joides Resolution) feels like.
Below you can see a picture of the cabin I am sharing with one of my female colleagues. We are lucky in that we scored one of the biggest cabins with a private bathroom. For most other scientists the cabins are significantly smaller and the bathroom is shared with another cabin. I am sleeping in the lower bunk and find it quite comfortable. The only downside of our cabin is that we do not have a window! From the beginning of the expedition on I started getting into a routine of visiting the gym every other day. It is good enough equipped that everybody can find some of their favorite machines for workout. Moreover, we are very fortunate that we have a great Yoga teacher on board (Paleomagnetist Lisa Tauxe). She gives Yoga classes every other night at 1am, which is right after the end of my shift. I am not going every time, but it is the best thing to do after a tiring shift, and Lisa is simply fantastic in monitoring the different levels of abilities in the group and adjusting her program accordingly.
Our cabin - quite a lot of space for a ship!
The first trip after waking up in the morning is usually to the mess. The mess on a ship is the place where people eat – just like a cafeteria back home. Our mess is quite spacious and offers place for about 40 people to eat at the same time. There is a coffee machine, an ice machine, a fridge, a toaster, a microwave, soda machines, and a constant supply of cereals and deserts. Food is served four times a day by the galley (kitchen) personal: 5 – 7 am/pm and 11 – 1 am/pm. During these times the mess becomes the social hot spot of the ship, where besides eating also a lot of information exchange happens (just like in the real world). The quality of the food is reasonable, but by now we are out of fresh stuff, and the same dishes tend to reappear on the menu…
Mess hall - this is where we take all our meals.
Arguably one of the best thing about life on the ship is that we do not have to do our own laundry or cleaning of the cabins! We can leave laundry bags with dirty laundry outside our cabin, and some 12 hours later the bag comes back with clean and folded laundry – heaven for people like me who hate doing laundry. A big thank you to the stewards doing the work on the ship.
This week we finished our first drill site, which was Site WLRIS07 on the map. The primary science objective for this site was to recover a distal record of the first arrival of glaciers to the eastern Wilkes Land margin. This is thought to represent the Earth’s transition from a ‘Greenhouse world’ to an ‘Icehouse world’ some 33 million years ago. We drilled the seafloor in 4000m water depth and recovered sediments from down to about 1000m. The material is truly spectacular: we recovered sediments from about ten different lithostratigraphic units ranging from very biogenic material over glacial deposits to very clay-rich material. We also found layers which were very rich in ice-rafted debris. Most of the material is of Miocene age (~5 to 23 million years), but we also found some older material (Oligocene and Eocene). Stay tuned and follow all the science results to come out over the next years – I am sure they will bring our understanding on Antarctic glaciation to a new level!
Map with locations where we plan to drill during the Wilkes Land IODP expedition.
After completion of drilling at Site WLRIS07 we collected all the drill pipe and moved over to the continental shelf. Under bright blue sky we arrived at Site ADEL01B, where we are currently drilling in a place where a lot of sediment was deposited very fast over the past ~10,000 years. This project was an add on to the original drilling proposal, and has the objective to recover a high-resolution record of the Holocene (the past 10,000 years). So far things are going well.
My personal highlight was that for the past two days we could see the Antarctic ice sheet. We are only about 30 miles off the coast of the continent. Due to the spectacular weather we can actually see the continent, and a large number of icebergs grounded right in front of it (see picture) – I will remember this view for a long time to come …
View on the Antarctic ice sheet with icebergs in front of it - what a day! Photo credit: Dan Brinkhuis.
And here is the third episode of our weekly videos from the Wilkes Land IODP expedition. This week is featuring Saiko Sugisako, a palaeomagnetist on the ship, and also my room mate. Enjoy!
