I was so lucky to have Steve ask me to help him with his video conferences yesterday. It was so fun to tell about our experience so far and to answer some of the questions from the students. And I see that some more questions have come in on my blog. All are really good – so I thought I would address them with a new blog today.
How do we know where to drill? Deciding where to drill and how deep is a very tricky business. We leave that work to the Co-chiefs. All our sites were very well researched and planned years before hand. Because we are interested in glacier history, we look for locations that have sediments of a certain age. For example, one of our goals was to recover sediments that can tell us about the transition between a Greenhouse Antarctica (which was warm and covered with trees) to an icehouse Antarctica (which we see today – covered with ice). These kinds of sediments are approximately 33 million years old.
How do we know where these sediments are? Well geologists use seismic maps which are made by sending sound waves off of a boat. The sound waves bounce back and tell us about the layers in the sediment. Kind of like how whales use echolocation.
See my picture below (taken from the Integrated Ocean Drilling Program Expedition 318 Scientific Prospectus) – This is a map of the sea floor and shows the co-chiefs where the different layers in the sediment are. The hard part is trying to determine which layer is which age. This is done by comparing the maps to previously drilled areas, looking at the slopes and layers, thinking about known processes, and with a little luck – one can make a good guess at what time period these layers represent. In this case, our co-chiefs decided that to get the age we wanted, we would have to drill to the red line, which they labeled as U3. You can see in the picture that the WLSHE-09 sites reaches the U3 line at a shallower depth than the WLSHE-07 sites. This makes these 09 sites better than the 07 sites. Unfortunately both sites were under ice much of the time, so we actually had to drill a bit further away – out of the picture where the water is very very deep, and where the U3 line is also very deep under the ground. Drilling this deep takes a long time, and thus not our first choice, but you take what you can get.
How do we know when to stop drilling? That is what Dr. Steve and the rest of the paleontologists are for. Paleontologist is a big word – basically a paleontologist looks for small fossils in the sediments. These fossils can tell us the age of sediments. When we see that the fossils match the age we are looking for, we know we can stop and move on to our next site.
What happens if the drill breaks while we are at sea? Well things do sometimes break out here – but we are always prepared. We have extra pieces, drill bits, everything we would need. We also have a great crew who know how to fix things.
What happens if the drill gets stuck? That can happen too. If that happens, we need to cut the drill off, pull up as much as we can and then fish the rest out.
What is the coolest thing I’ve seen so far? I love seeing bioturbation in the core. I’ve already posted this picture before, but it is just so cool that I will post it again. Do you see all those swiggles? Those are old tracks made from worms, or other little creatures that used to live in the sediment. After a while the tunnels they make get filled – the sediment is a different color, and we can still see their tracks. Remember I love biology – so seeing tracks of living things is very cool for me.
What is the most unusual thing I’ve found in the core? Well I don’t know if I would call this unusual, but I would definitely call it smelly! We brought up some cores that had hydrogen sulfide gas – which smell super bad. I don’t know if any of you have ever visited a volcano, or Yellowstone, but those are some other places where you might smell this kind of gas. The gas is made from the bacteria in the sediment – so of course I love it! Why do they make it? It is their way of making energy, and allows them to live in a environment without oxygen.
Have we ever found oil? No – we actually avoid it, just not what we are looking for.
Do we have satellites? Yes – The satellites are very helpful. We have some satellites that tell us our GPS position, so we know where we are, which is very important because most of the time we cannot see land. The satellites also bring us our internet and television connections which allow us to send work back to home. It’s great hearing from people at home! Though sometime we lose connection. This can happen just when the ship turns. That drilling rig is so big, that it can easily block the connection if we don’t move the satellite dishes around it.
What happens in a storm? Well, sometimes we have to stop working outside at the drilling rig if the weather gets really bad. We have to make sure that all the people working outside are safe, and it can get really wet and windy in a storm. Also we have to watch out for icebergs. The storms can move the bergs quickly and we have to make sure that we get out of the way if one comes close. But we can still work upstairs in the labs. But you have to be careful not to spill anything and make sure stuff does not move around. Everything big, and every big instrument on the boat is bolted down to either a table or wall. They are very expensive and it would be a shame to have anything fall on to the ground.
I hope that helps! Keep the questions coming. We are drilling out last site now. We will be working here until Tuesday I think when we will start to head back to Hobart. It will then take about 6 days to get there. Someone asked when I will be going home – and the answer is not until March 22nd, because I’m going to take a little vacation in Australia – might as well right? 🙂