Arrived on Site in Baffin Bay

After a 6-day transit from Iceland across the Arctic circle and into Baffin Bay, we have arrived on site offshore northwest Greenland and the ship is positioning itself across the first target site. At the same time the drillpipe is being put together. First, the thrusters have been lowered. These are large propellers that can move the ship sideways in addition to forward. During transit these propellers are raised up above the deck (see grey column in top picture). Once lowered, a computer controlled dynamic position system that works with GPS, is firing up the thrusters one by one to keep the ship in a stable position across the site. 

We were on a tour of the drill rig floor this morning, under the derrick, and we could see the pipe sitting there, ready to be put together into the drill string. The length of the pipe segments is checked for in manual measurements. Now that we are on site, the crew will put together an approximately 2 kilometer string of pipes to reach the seafloor beneath us. At the bottom of the pipe is the bottom-hole-assembly, or the BHA for short, which includes the drill bit that makes the hole in the seafloor. Here is a picture of the drill collars that rotate and get us into the seafloor.

Expedition video trailer

We are scheduled to take fuel tomorrow and to start our journey the day after. Expedition education and outreach officer Beth Doyle made this video trailer. Enjoy!

IODP Expedition 400 is about to begin!

International Ocean Discovery Program (IODP) Expedition 400 will depart for Baffin Bay this week. Today the science party is scheduled to move to the research vessel JOIDES Resolution in Reykjavik, Iceland. The objective of the expedition is to recover sediment cores from seven sites on the Northwest Greenland continental margin to obtain a paleo-archive of the behavior of the Greenland Ice Sheet during past warm periods. Melt of the Greenland Ice Sheet is currently contributing to sea-level rise worldwide and its behavior in the geological past will shed light on the end point of this melt in the future. Stayed tuned for more.

The longest core off West Antarctica

We are back in port in Punta Arenas, Chile, with on board many sections of drill core. This IODP (International Ocean Discovery Program) expedition was definitely the most challenging I have been part of. We drilled two Sites into the newly named Resolution drift, a mound of mud off West Antarctica. Drilling conditions were very difficult with many icebergs. However, thanks to the fruitful collaborations between navigators, scientists, engineers and drillers, we were able to extract a long and complete geological climate archive from beneath the seafloor. Never before did a ship recover so much core from a single site on the Antarctic margin as at our Site U1532. It is still a humbling experience to be part of such a large scientific and technological operation, even though this was my 6^th drilling season on the Antarctic margin!

The science team measured many properties using various instruments and microscopic observations and we are still processing the main findings. The scientists are trained in many different disciplines, from biology to chemistry to physics, because geology (or geoscience) is an interdisciplinary science. A few examples of types of shipboard measurements and observations are described below.

Lithologies (sand or mud) and sedimentary structures: like the cross-sections of ripples in the sand on a beach, but here encased in deep-sea mud. The ripple structures tell us something about variations in how fast the deep ocean currents were flowing. These currents are wind-driven or gravity driven (like rivers), so indirectly they let us know how strong the winds were in the past or how much material was coming down from the continent in deep-sea channels.

Cobbles and pebbles:  the rocks are full of mineral crystals that point to a type of volcanic process. Some of these rocks are unique to specific locations in West Antarctica. The rocks were taken up by the glacial ice and transported offshore as icebergs broke off from the land ice. Hence these rocks tell us about the locations on West Antarctica where ice was released into the ocean by the calving of glaciers in the past.

Physical properties: for example, how fast sound waves travel through a rock core is determined by how dense and springy the material is. Sound waves travel fast in hard, cemented, layers (see also below). The natural radio-activity of the cores is another physical property that is measured. The natural radio-activity is lower when more fossil material is present, which is not as naturally radioactive as material brought in from land. In the Antarctic ocean, we can use the natural radio-activity of core sections together with microscopic observations of fossil marine algae to estimate how often open ocean without sea ice was present through time.

Pore water chemistry: water within the rock was squeezed out (see squeezers to the right) and analyzed chemically to understand how sediments and water change down to hundreds of meters beneath the seafloor. For example, we found layers of sand grains that were cemented together into a hard rock, like concrete. The compounds that make up the cement typically come from the pore waters. To tie all these different measurements together, we have had integrated meetings with all the 30 or so scientists on board. 

In the next few years we will be able to write the history book of the West Antarctic Ice Sheet and how it developed through past warm periods using the shipboard data and additional measurements in shore-based labs. We will be able to place the present accelerating melt of the floating glacial ice in the Amundsen Sea embayment into a long-term framework of many generations and in the process educate the scientists of the future!

The ship is now made ready for Expedition 382 Iceberg Alley, another Antarctic expedition with the JOIDES Resolution drillship. Our shipboard crew and science party will leave the ship on Wednesday and a whole new crew and science party will get on board. If you are interested in following the Iceberg Alley expedition, make sure you follow @jr on Twitter and blogs could be available at joidesresolution.org. 

Life on the JR: we still have pineapples!

We have been drilling down hundreds of meters into the seafloor and we have been processing a lot of core. At the moment we are waiting on ice, so time for another blog post.

Imagine you are staying at your work, school or university building for two months without the ability to run to a store and shop. Your friends and colleagues are with you, but not your family. When you look out of the window you see the most beautiful scenery with icebergs and when you step out on the balcony you can sometimes observe the breathing spouts of a group of humpback whales. That is what it is like to be on the JOIDES Resolution in the Amundsen Sea near Antarctica, but our balcony is the deck and we are a long way from home.

We are a total of around 120 people who work different shifts. We are drillers, scientists, operation managers, laboratory techs, engineers, ship navigators, ice watchers, artists, educators and human services personnel, etc., and we all have an equally important part in this whole operation. The nightshift works from midnight to noon and has breakfast, lunch and dinner together at odd times. We also celebrate birthdays: here a picture of Thomas the nightshift paleomagnetist on his birthday last week (photo from Tim Fulton). There was a really nice cake and it was a joyful celebration.

Today we learned from Steve, the chief steward, about the 15 people who keep us happy and allow us to do work 12 hours each day. They do an excellent job preparing and serving our food, doing our laundry and cleaning our rooms and common areas. We also learned from Steve how much planning goes into a shipboard expedition with 120 people with no opportunity to shop for food for two months. You can bring bananas for the first week, but after one week bananas go bad so you need to come up with some other fresh fruit for people to eat the remaining 7 weeks. In his food purchase for two months, Steve makes an educated guess about what kind of food people might like and takes into account that in Antarctica people eat more food to keep warm, especially those who work outside.

Apples and pears can last pretty long and we still have them along with slices of cantaloupe, but the fresh pineapple chunks had been extremely popular after the bananas had disappeared. Unfortunately, the last couple of days we noticed a decline in the pineapples among the cut fruit and we began to worry. Luckily, today as Steve took the nightshift lab folks on a tour of the kitchen and food stores, we could see with our own eyes that we still have pineapples! (I also found out that my cabin is across from the store room with the Oreo cookies in it, but the door has a pad lock on it….) By now most of the fresh vegetables we are served are hardy ones, like carrots and cabbage. But today we had hamburgers with fresh tomato slices! That is pretty amazing, considering that we left port a month ago. We are taken care of really well, thanks to Steve and his team.

Dancing with icebergs: the re-entry cone

Due to the unexpected erratic movements of icebergs, we have had to pull the drill bit up in the hole or even out of it above the seafloor many times in the past week. The ship is unable to move with the drill pipe stuck in the seafloor and it takes time dismantling the stands of pipe so that it is short enough to hang free above the seafloor. Only when the pipe is hanging free, the ship can move. Therefore, if an iceberg comes within a mile of the ship it is closely monitored and a set of safety measures take effect, which include raising the drill string out of the hole. Typically, if there is enough time and the iceberg keeps approaching slowly, a large approximately 3-m (10-ft steel) funnel is lowered over the drill pipe to the seafloor. Unfortunately, icebergs have been coming at us at higher speed than expected and with unpredictable paths, so we have not been able to deploy a free-fall funnel. Finding back the drill hole without a free-fall funnel after leaving the location is very difficult, and if it takes too long, the hole will cave in.

Rest assured: engineers here on board can fix EVERYTHING (I am not exaggerating). So, the crew got to work to build a re-entry platform, so that we can find the hole more easily and make it more stable so we can move the drillstring in and out if we need to move the ship for icebergs. It took some time to put the re-entry platform together, but it was launched a few hours ago. The re-entry system consists of a free-fall funnel attached to a platform with an 11-m long pipe that is large enough to fit the drill string. The platform serves as a mud skirt, making sure the funnel doesn’t sink too far into the fluffy sediment at the top of the seafloor.

The moonpool is a hole in the middle of the ship through which the drill string passes. To launch the re-entry system, the doors of the moonpool had to be opened wide for the platform to pass through. This was a tricky operation, because we are also currently operating in high waves, but Bubba, the toolpusher, and his crew are very experienced. The spectacle of launching the re-entry cone was watched by many science party members. Everyone was freezing, but it was worth it (The drill crew who are out there everyday in the wind and snow deserve a lot of respect). After the launch it took the funnel and platform about 17 minutes to get to the bottom of the ocean, sliding down along the drillpipe for about 4 km. The funnel has a white interior, like a target, so that it is easy to find if a re-entry is needed. Now fingers crossed and let’s hope it works!

Ancient icebergs and polar oceans

The team I am part of on board the Joides Resolution, is the Sedimentology team. We have several jobs: one is to X-ray the core sections that come up to see if something interesting is embedded inside. Once the X-rays look good, the cores are split into half sections across the length of the core and we describe the mud and layering we see. We also take smearslides and look at minerals and microfossils. The shipboard lab has special tables to lay out the half core sections so that we can see the layering inside and any disturbance of the layering caused by drilling. The Sedimentology team also uses instrument tracks to take full-length digital images of the sections, and to measure their color and magnetic properties. The photo above shows my fellow night shift sedimentologists, Benny Reinardy and Ruthie Halberstadt, at work in the sedimentology lab.

Both in the X-rays and in the split core we find layers that include rocks and minerals that were dropped from ancient icebergs as they melted. Icebergs are made of pieces of land ice that have broken off glaciers in the ocean. Even though these icebergs may have melted millions of years ago, the rocks and minerals are the scientific evidence of the iceberg’s existence in the past and can be used to trace the paths of icebergs in the ocean currents. The rocks dropped from icebergs (ice-rafted debris or IRD) in the layers we describe provide us with one way to gain knowledge about the past environment and climate in the Amundsen Sea. Some layers contain ice-rafted debris and some don’t. The X-ray image shows a picture of density changes. Rocks “floating” in the mud are hard and dense and they show up as dark blobs, whereas the mud around it is soft and less dense. The X-rays travel through the soft mud, but not as well as through the dense rocks. It is the same when you take an X-ray of an arm or leg with a broken bone: the bone is denser than the tissue and the X-rays make it visible.

We also keep track of evidence of ancient life embedded in the layers. The food chain in the Antarctic Ocean is quite special. We have seen humpback whales around the ship, which feed on krill. In turn the krill feed on microscopic plants called diatoms. Even today diatoms are at the bottom of the food chain here in the Southern Ocean. Depending on the environmental and climate conditions in the past diatoms were blooming here in the Amundsen Sea or not. Also, different types of diatoms do well in different environments. We found the type of fossil diatom above in several of our smear slides samples from the core. Its name is Eucampia antarctica, it looks like a fancy letter “C” and it likes cold polar ocean environments. However, other diatoms don’t like to live in the cold at all and the paleontologists have found fossils of these types of diatoms as well.