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.

Core on deck!

The Joides Resolution is drilling in more than 4 km of deep water in the Amundsen Sea and we are surrounded by icebergs every day. This provides for some beautiful scenery, but it is not always good for drilling if they are coming straight at us! Several times over the past few days we have had to pull out of the hole with the drillstring, and move the ship out of the way of a passing iceberg, and we are now in our third hole at the same site. The good news is: we have recovered beautiful complete cores going back in time several millions of years including through prominent warm periods. These archives of the ice-sheet’s history will allow us to retell the story of how the West Antarctic Ice Sheet behaved in the past under warmer conditions.

After some foggy days, which were really difficult for the ice watchers, the weather has cleared and the ice watchers can better track the movement of icebergs. The ice watchers, which include the captain and his crew, use three different ways to make sure an iceberg is not impacting the ship. First, they use satellite images to map the track of large icebergs. However, smaller icebergs are not visible at the scale of the satellite images they use. So, for smaller icebergs down to a size of approximately 5 m across and more than 1 m high, the shipboard radar is used. Individual icebergs are numbered and their tracks are mapped on the radar. Lastly, icebergs that are less than 1 m high above the sea and less than 5 m across, so-called growlers and bergy bits, are difficult to observe on the radar. These smaller icebergs are spotted by eye from the bridge. The smaller icebergs have been causing us the most trouble in the fog, but now that it has cleared we are back on track.

Cores come up in 10-m long segments every few hours ("Core on deck!" on all speakers). In the photo you can see the 10-m long tube with sediment (the core) being carried onto the catwalk by the core technicians. On the catwalk the core is cut into 1.5 m long sections so that it can fit through the shipboard labs. The sediments are hard now, and core sections are being split in two halves with a motor saw, whereas previously the soft mud could be cut with a wire. After piston coring for more than 200 m down into the sea floor, we are about to change over to the XCB rotary coring system to drill farther down into the rock and to uncover the early history of the Amundsen Sea’s ice behavior.

Arrival in Antarctic waters

We are now at more than 66 degrees South and will soon cross the Antarctic Circle. Yesterday water temperatures plumeted to 0 degrees overnight, and we saw our first iceberg early that morning and many more since. Activities are ramping up across the vessel as we approach our first drillsite. Everyone will be on their shifts tonight (midnight to noon for me). Drillers are getting ready. The co-chief scientists, ice watchers, and operational personnel had a meeting yesterday to assess the ice conditions for the drillsites. Drilling will commence at a deep-water site in the Amundsen Sea after the captain has had a chance to monitor the ice conditions on site.

To get a drillbit into the sea floor the drill crew will need to assemble more than 3 km of drill pipe. On board the ship sets of three approx. 10-meter sections of drillpipe have been assembled into "stands". So, now imagine you are a driller: how many stands of drillpipe does the drill crew need to fit together to reach the sea floor? It will take some time to do this, so once we are on site and the captain is comfortable with the ice situation, it will take about 12 hours before we can start drilling with the more than 3km long drillstring. Imagine that!

The drillers initially will use two different drilling technologies. First, the piston corer is used to about 150 meters below sea floor. The piston corer consists of a 10-meter long hollow metal tube with a sharp edge, which is shot into the seafloor under high water pressure, like a syringe. The metal tube cuts like a knife through soft mud, which then fills a plastic liner inside the tube. Below 150 meters below the seafloor the sediment layers are much harder because of compaction due to the weight of the overlying stack of layers. Once it becomes difficult to advance the piston corer down into the rock formation, a rotating core barrel with a toothed edge will be used to cut into harder rock.

Reed's dirty little secret

Yesterday we entered the Drake Passage and the seas were so rough that many had to retire to their cabins to avoid sea sickness. Today conditions are much better and the sedimentology team, that I am part of, invited a well-known Antarctic paleontologist, Reed Scherer, to explain the correct process of making smear slides. And: Reed revealed his dirty little secret, which involved a potato and some ballet movements.


So what is a smear slide? A smearslide is a smear of sand and mud from the drillcore on a glass slide, so that it can be viewed under a microscope. The sedimentology team uses smear slide observations to characterize microfossils and minerals in the sea floor sediments. The fossils tell us something about the living conditions in the ocean around Antarctica thousands to millions of years ago. The minerals would tell us something about the rocks on Antarctica the glaciers were eroding, because rocks are made of different minerals. More about that later. The image shows an example of microfossils of a group called Radiolaria, a kind of zooplankton.

So how to make the perfect smearslide? Well, the sediment needs to stick to the slide. Water doesn't work, because it creates a droplet, so you can either lick the slide, or...... use a potato! The potato is very important. First of all, it needs to be clean, so no microfossils or dirt sticking to it. Second, you need to take care of your potato: wrap it in foil after use and store it in a refrigerator (I think we may get only one potato for the entire expedition?). The potato is used by rubbing your finger over a cut face so that starchy liquid can be transferred to a thin glass cover slip. This is then where the mud will stick. Then, the cover slip with mud is left on a hot plate to dry after which the glass slide is put on top of the cover slip. This involves a special type of coordinated movement: closing the two glass slides on top of each other like the jaws of an alligator, while bending the knees. Reeds says it doesn't work if you do not bend the knees, so that is also very important. We have all been practicing bending our knees and we hope to be experts by the time the first core gets on deck!

In transit to Antarctica

We left yesterday, on January 23, and took the route from Punta Arenas through the Magellan Straights into the Atlantic Ocean, because low pressure systems with high wave heights were present to the West. On the map is our ship's location near the tip of South America and the Antarctic Peninsula projecting North. The map at the bottom is the wave height projection. This information is available on monitors around the ship. At present we are passing between Isla de Los Estados and the Argentina mainland. The ship crew is enjoying the last views of land before we enter the Southern Ocean. The red line is the track we might follow through the South Pacific, although we will probably deviate from it to stay away from strong storm systems. We will probably arrive on our first site in Antarctica around February 1, weather permitting of course...

Getting ready to leave Punta Arenas

We have been enjoying some nice last evenings onshore: it is Summer here and there is daylight until after 10pm. But: the JOIDES Resolution is now being prepared for departure. All scientists are on board the ship and the crew is complete. We are still waiting for some heating and communication equipment and we will leave port as soon as that arrives.

The captain and his crew are preparing the passage plan to the Amundsen Sea. Equipment is being secured for a possible rough passage with high waves. Today we inspected our life vests and tried on our survival suits, which is routine at the beginning of each voyage. Because of a newly adopted international Polar Code we will adhere to a number of new safety measures. The shipboard equipment, including cranes, are serviced for freeze protection and everyone on the ship will go through Cold Water Operational Safety training, which will take place tomorrow morning for the scientists and JRSO staff.

Unfortunately we will likely not have internet coverage during most of our time in the Amundsen Sea because the satellites are very low near the horizon as we operate in that part of the world (it is a communications "blind spot"). Iridium phones are used for data traffic, weather and sea-ice reports. Daily and weekly reports will have priority over social media communications, so if you'd like to find out what is going on and nothing is posted here, you can check for operational and science reports on the website of the JR Science Operator.

Getting ready for Port Call IODP Expedition 379 Amundsen Sea

I am about to embark on another Antarctic Expedition with the International Ocean Discovery Program (IODP)! This is the first time that the drillship Joides Resolution will be visiting the Amundsen Sea Embayment of Antarctica. No ship has ever drilled deep into the seabed in this area. Hence we know very little about its history.

The Amundsen Sea today is the focal point of ice discharge from West Antarctica into the ocean. An area roughly the size of California in West Antarctica is losing ice at an accelerating pace. Scientists are questioning whether this is a response to recent warming of the oceans and would like to know if there is a point of no return beyond which ice can be lost permanently or for a very long time. Two IODP expeditions, one to the Ross Sea (Exp. 374) and the current one to the Amundsen Sea (Exp. 379) are addressing this question.

By drilling into the sea bed, geologists can access deeper layers that date from before the last ice age and find out how the ice sheet behaved under warmer climate conditions in the past. In fact, today's developments are like an incomplete movie: we cannot yet see the end of the ice-sheet change. By going into the geological archive of past climate changes embedded below the sea floor we can reconstruct the full cycles of ice growth and melt from beginning to end over hundreds to thousands of years. Such a complete story of ice-sheet change will give us information on whether its current behavior is outside the normal range, and will help predict how the ice sheet may behave in the future.

I will be leaving for the port city of Punta Arenas, Chile next week. I am currently packing and getting ready for a 2-month stay on a drillship without an opportunity to get off! See you soon.