ABOARD THE JOIDES RESOLUTION, IN TRANSIT TO HOBART, TASMANIA– The work of the ship ended as quickly as it started nearly two months ago. We finished drilling Site 1361 and logged the hole. The drillers tripped 3500 meters of pipe and prepped it for storage as the ship will not drill again until July – off the coast of British Columbia. Everyone on board is absolutely brain dead from the non-stop grind of 12-hour shifts day after day. But all are happy as well. We’ve completed most of our objectives and made some exciting discoveries. When we did not meet with complete success it was always because of weather and ice, either encroaching sea ice or fields of icebergs so thick that we had no chance to pass.

Relaxing with some music after the work is done.

Now we have some days in transit. These days are filled with meetings to design our post-cruise research. We will all spend much more time at home working on the cores than our actual days at sea on this expedition. Some of the methods we will employ are expensive and difficult and we have recovered nearly 2000 meters of core. This means that we must carefully select the intervals we will study, so that we can answer the most important questions about Antarctic climate change as quickly as we can. For some of us, the analytical work will extend over the next 4 years. Then other scientists will work on these cores for decades to come. They will be stored in a vast library of ocean cores in College Station, Texas, at the IODP core repository where they are available to scientists from all over the world.

What I like most about these days in transit is going off shift. I no longer set my alarm to awake at 11PM. The two shifts mingle at meals and in the labs, almost as strangers at first as they have not seen much of each other for more than 7 weeks.

The whole team for Expedition 318. Photo courtesy of John Beck, IODP.

Working groups between the shifts assemble to design research strategies and timetables. I will lead a group that will make oxygen isotopic measurements of the small shells of amoeba-like organisms called foraminifera. Forams, as we call them, live for about 4 weeks during the brief Antarctic summer. They build their tiny shells out of calcium carbonate, the main mineral that makes up limestone. By measuring the ratios of two types of oxygen in the carbonate we can tell the temperature of the water in which the forams grew. We will make these analyses on forams that were living in Antarctic surface waters hundreds, thousands, and even millions of years ago to see how warm the water was next to the Wilkes Land coast. We already know from our microscope work on board that this part of Antarctica has been very warm at times, maybe 10 to 15 degrees centigrade warmer when we go back 35 million years. The foram work will help tell us exactly how warm the waters may have been during more recent periods when we know the ice sheet became much smaller. The results will help us predict the behavior of Antarctic ice in the future.

What a trip it’s been! I hope you’ve enjoyed these blogs. If you live in the Bay Area, please look for a notice about a talk I’ll likely give on this expedition in 6 months or so, after we’ve had a chance to start the shore-based part of the work. As we pull ever closer to Hobart we are very much aware that we are simply reaching the end of the beginning.

Christina and Joerg at the bow at sunset. Photo courtesy of John Beck, IODP.

Drilling at Site U1361
Position: 64º 24.6’S, 143º 53.2’E
Water Depth: 3470 meters
11 more days!

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Hi folks! We’ve been busy the past 9 days. We are coming to the end of our work window here in Antarctic. Summer has ended, the nights are much longer, and next Tuesday we must begin our transit back to Hobart, Australia.

We made our last attempt to get into one of our continental shelf drilling sites but were stopped once more by sea ice. All of the ice here is frozen seawater as opposed to glacial ice.

The sea ice is porous and inside the pores are salty brines that support plant and bacterial life. Here we are trying to collect so ice, but it’s a long way down to the water for this little bucket, especially when working from a moving ship.

We finished drilling deep into the seabed at Site U1359, encountering sediments and rocks that span much of the last 13 million years. For several hundred meters we found layers of rock that alternated between green and brown over distances of 2 to 4 meters. The green parts of the cycle showed evidence of intense mixing of the sediments by animals living at the seafloor while the brown parts showed something quite different – very well-developed laminations that could not have survived if the sediments were mixed. There were different materials in the layers too – some contain more shells of diatoms, the main plant in the surface waters of the ocean. We don’t yet know what these cycles of green and brown represent but we think they reflect the continued glacial-interglacial cycling of the Earth’s climate many millions of years ago.

Today we are in a very cold period in the long-term history of the Earth, and have been for most of the past several million years. Because the Earth is already quite cold, when we have glacial-interglacial cycles, we see large ice sheets coming and going at both poles – in Antarctica, Greenland, and over large parts of North America and Scandinavia. This waxing and waning of polar ice is driven by small changes in the shape of the Earth’s orbit around the sun (it changes from an ellipse to more circular and back again over about 120,000 years), the tilt of the Earth’s axis (it wobbles a bit over 40,000 years), and the exact seasonal timing of when the Earth is at its closest approach to the sun. All of these “orbital” changes impact how much sunlight reaches the Earth as well as when and where it warms the Earth seasonally. Sometimes, the Earth is in an orbital configuration that produces warm winters and cool summers – a combination that usually allows ice sheets to form and grow. Some 10’s of thousands of years later, the opposite occurs – warm summers and cool winters – which can cause ice sheets to rapidly melt. In today’s cold world, these small changes have big effects as the Polar Regions are cold enough to allow large ice sheets to form and last through the warmer periods. Antarctica has been covered in a large ice sheet for many millions of years because of this overall cooling. It still waxes and wanes along its margins but it is always present in the continent’s interior. But prior to about 2.5 million years ago, there was no permanent ice sheet in the north polar regions – it was simply too warm. Further back in time, the Antarctic ice sheet was much smaller than it is today but it was still dancing to the rhythms set by the Earth’s orbit.

What we were seeing at our last drill site and what we are looking for at our latest site is evidence of how these glacial-interglacial cycles affected the Southern Ocean and how they in turn may have been different because the planet was a little bit warmer than today. By studying this we can learn more about how small changes in the planet’s temperature can affect things like ice volume, sea ice extent, and the productivity of the ocean. This is directly relevant to understanding our Greenhouse future. Although all the climate variability that occurred millions of years ago was “natural” (in other words, not caused by people), the strength of the signal that caused these past changes (the orbital changes in this case) is not very different from the strength of the signal we expect from the man-induced increase in carbon dioxide levels in the atmosphere.

The poles are a great place to study both natural and man-induced changes in Earth’s climate because of a phenomenon called polar amplification. We know from many hundreds of studies of the past 50 million years of climate change that whenever the Earth warms up, the poles warm up more than the planet’s average. The converse is true for times of cooling. We don’t yet fully understand the reasons why but based on these studies of the past we shouldn’t be surprised that the poles are warming up very quickly today, at a rate greater than what we see in the tropics or the temperate belts. The cores we collect on this trip have the potential to tell us more about when and why polar amplification occurs.

I’ll send one more blog from this trip once we have cleared our last hole and are heading for Hobart. Sixty days is a long time to be as sea and working every day for 14 hours or more. We are all excited to get home.

I had a chance to get off the JOIDES Resolution a couple of days ago when we were running a “man overboard” drill. We recovered the dummy and then I was able to take these shots. It was our warmest, sunniest, calmest day by far. You’d never know we were in Antarctic waters.

We’ve been seeing lots of whales at our continental rise sites. The whales come to Antarctic waters in summer because of the abundance of food.

At dawn one day, we had more than 35 Humpback whales around the ship. From a distance you usually first see their spout, which you can make out here.

More storms and more icebergs. This seems to be the story around here now. Once each week we get a major blow and the seas kick up.

Then when we are near the continental shelf we see more icebergs…..

Transiting back to Site U1359
Position: 64º 34’S, 140º 30’E
Water Depth: 3700 meters
The scene outside: 2 days of storms and lots of icebergs

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Our latest drilling target is in an area where sediments that document the transition of Antarctica from the “Hothouse” to the “Icehouse” can be easily reached at shallow depth beneath the seafloor. We drilled for 18 hours and then had to pull the drill pipe up out of the hole and reposition the ship to avoid a large iceberg that was heading straight for us. When the iceberg had passed the weather started to deteriorate. Our forecast was for 60 kt winds and big seas so we headed north out of “iceberg city” to ride the storm out in deep water away from icebergs and sea ice. The forecast was true to its word – we had waves up to 30 feet and winds over 60 kts for more than 24 hours. But we had great iceberg viewing on the way to our WOW (Waiting On Weather) point so I’ll write something about them and how they fit in with our project.

The Antarctic ice sheet is always accumulating new snow that gradually turns to ice. For the ice sheet to remain the same size it must either melt or release ice to the ocean as icebergs. In parts of Antarctica some of the ice is in fact melting but most of the ice loss that maintains the continent at its present state occurs through the calving of icebergs. Most icebergs calve off of ice tongues and ice shelves – areas of concentrated ice flow at the coast. Imagine that the ice is draining off of the high parts of the continent by flowing down small ice drainages to form mighty rivers – but rivers of ice in this case. These vast rivers move slowly, only a few 10’s to 1000’s of meters each year. When they reach the coast, the ice flows out into the ocean where it begins to float wherever the water is deep enough. In some cases, this is where the water is over 500 meters deep and the ice is over 560 meters thick. Floating ice shelves or ice tongues are influenced by winds and ocean currents. They begin to melt if the water is warm enough but they mostly breakup to form icebergs.

Many of the icebergs here off Wilkes Land came from the Ross Ice Shelf – the world’s largest ice shelf. It is over 1500 km away in the Ross Sea but icebergs travel great distances in the Southern Ocean. The water is cold and they drift with the ocean currents, for decades in some cases. As they drift, they melt a bit below the waterline and become rounded. Sometimes they flip over and this rounded part is then visible. Icebergs often collide and gouge away at each other or they list over at an angle and slowly fall apart. This means that icebergs come in all shapes, sizes, and textures.

The biggest iceberg we’ve seen was over 20 km long.

Icebergs come in all colors, from the pure white of fresh snow to the deepest blue of pure crystalline ice from far below the surface of the ice sheet.

Icebergs come in all shapes, sizes, and textures.

A penguin on a growler (a small iceberg).

The ice at the base of the ice sheet often carries sediments: boulders, gravels, cobbles, and sands. When these parts break off and begin to float they form “dirty” bergs with dark rocky layers intermixed with the clear blue ice. The debris that falls from these dirty bergs accumulates in sediments at the seabed. When we see gravels or sands in otherwise fine-grained sediments, we know this debris was transported out over the ocean by ice. In fact, the presence or absence of ice-rafted debris is something we keep close track of in the cores we are collecting on this trip – this tells us whether Antarctica was generating lots of icebergs and therefore had at least some kind of ice sheet in the past. Conversely, when we see sediments that do not contain this debris we know we are looking at a record from a time when Antarctica was much warmer.

In the foreground, a dirty iceberg.

We’ve seen over 400 icebergs in the past 2 days.

As I write, the storm has abated and we are transiting back to our drill site.

Dawn at 4:30.

At Site U1356, Hole U1356A,
Position: 63º 18.6139’S, 135º 59.9397’E
Water Depth: 4003 meters
Core Depth (penetration into the seabed): 1004 meters
Total weight of over 3 miles of pipe hanging from the ship: >650,000 pounds!

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Wow! What a week! We just finished retrieving our final core from the bottom of a drill hole more than 1 km in length. We’ve now recovered and described sediments that range in age from a few million to more than 36 million years old, all in the span of about 9 days.

The first sediments that came up told us what Antarctica was like when the ice sheet was like it is today. Then we saw evidence of a much warmer time and then a colder time before that – a time when flotillas of icebergs carried rocks and debris from the Antarctic continent out over our drill site, dropping this debris as they slowly melted. Even further back in time, more than 30 million years ago, we began to find evidence of much warmer waters…and for the first time no evidence of large ice sheets.

Yours truly wearing a shirt to match the core: muds from Tasmania. Photo by Christina Riesselman.

We also began to see sediments that may have come from Tasmania or other parts of Australia. Even though we are now thousands of kilometers away from Australia, back in time, 30 million years ago, Tasmania and Antarctica were much closer, perhaps only 100’s of kilometers apart. Plate tectonics since that time has carried Australia to the north while Antarctica has remained more or less anchored at the South Pole. So, not only do our sediment cores tell us tales of past warm climates (and perhaps give us hints as to what lies ahead in our greenhouse future), they also tell us new things about the science of plate tectonics.

The weather here changes fast! Yesterday, we had a warm (well…..maybe 4°C) and sunny day – our first sunshine in over 3 weeks. After shift, EVERYONE went outside to feel the warmth of the sun and to see blue skies and blue water.

Our first sunny day on Leg 318. Vitamin D the natural way.

I was up for shift at midnight. It was calm and cloudy with snow at 4AM but by 9 AM it was blowing 35 kts and we now have waves over 20 feet high. The change in weather happened while we were retrieving our very last core.

The night shift sedimentology team working on 30 million year old sediments.

Moon set on the JOIDES Resolution, 31 Jan 2010.

Now we will spend another 2 days here doing something called “logging”. Logging the hole is when we send instruments down to the very bottom of the drill hole after we remove the metal pipe that now supports it. These instruments measure the properties of the rocks we drilled through. By doing so we can piece together the sections of sediment we actually saw and described, even across breaks in our core that may have been caused by problems with the drilling. Altogether, we usually recover about 50% of the rocks we drill through. Some of the softer or stony units just can’t be cored and recovered very easily so this kind of work, logging, is very important for us.

So, back to writing up our results and making a short video clip for you about the work in the lab – I’ll send that off tomorrow. It’s great fun out here and the time is going by very quickly, just about as fast as the short Antarctic summer…..

At Site U1356, Hole U1356A,
Position: 63º 18.6139’S, 135º 59.9397’E
Water Depth: 4003 meters

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Here we are on the 29th of January, 20 days out of Wellington, New Zealand, and exactly 1/3 of the way through our expedition to the coast of Antarctica. It’s been a fantastic week for everyone aboard. We have now drilled over 750 meters into the seabed off of the Wilkes Land Coast of Antarctica. We are operating far enough offshore that we are in deep water – over 4,000 meters deep. This means that we have 4750 meters of drill pipe hanging from beneath the ship. The entire length of pipe rotates a drill bit and we bring up sediment cores in 10 m sections about every two hours.

Core on deck – 8AM on Jan 29 2010. This core is from 750 meters below the seafloor and will be worked on for the next 10 hours by the shipboard technicians and scientists.

Cutting the Core from IODP Expedition 318 Site 1356 in Antarctica. This core contains rocks about 25 million years old.

The cores get run through a variety of tests on the ship. We measure how much magnetism they have and how much natural radiation they emit (all rocks and minerals on Earth emit very low levels of natural radiation). This tells us how old the cores might be. We then split them using a diamond saw (we are so deep it is real rock coming up now) and run more tests.

Core from 730 meters beneath the seafloor. It’s hard rock but used to be mud that fell down on the seabed 25 million years ago. There is about 7 meters of sediment here.

I am a specialist in sedimentology which means that I describe the sediment – is it mud? Sand? Does it have fossils? Are there features that tell us of past submarine landslides? The sedimentologists get to see all of the sediment cores that come up so it is very exciting. We have seen long intervals when icebergs were dropping off bits of the Antarctic continent as they floated by and melted. We’ve also seen periods when there wasn’t much ice at all.

A close up view of some of the rock we are collecting. Here you can see ancient worm burrows from small animals that lived that the seafloor. The sediment changes color when the oxygen content of the deep sea changes.

Another section of the core. These stones fell out of icebergs that melted and dropped to the seafloor. The scale is in centimeters.

Cathy Stickley, one of our micropaleontologists who tell us how old the rocks are. She is English but lives now in Norway.

The sediment core that just came up 10 minutes ago (photos above) contains sediments that are something like 20 to 30 million years old. We won’t know for sure until our micropaleontologists have a look but we are approaching a horizon beneath the seafloor where we expect to start seeing evidence that it was much warmer here – maybe 10 to 15 degree centigrade warmer than it is now and a time of no or little ice on Antarctica. We should be done drilling here in 2 more days. Then it’s on to the next site. I’ll keep you posted!

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– So, guess what? We had to abandon our first drill hole, the one I wrote about yesterday. Turned out we had drilled into a massive body of sand, gravel, and big rocks. This came from the bulldozer effect of the ice on Antarctica. The force of the Ice Sheet as it grew to the edge of the Antarctic continental shelf scraped off all this rock and debris and bulldozed it into the deep sea – and think of a bulldozer with unlimited horsepower and a blade 2000 km wide. The power of ice to erode the hardest rock and move it great distances is unmatched by any other natural process on Earth. We just HAPPENED to be trying to drill where a deep sea canyon or channel was taking the heaviest stuff. This was unexpected from all of our pre-drill site survey work, and to be honest, very unlucky on our part – there aren’t that many channels of this type out here in the deep sea.

Our drill could only go 40 meters into the seafloor before it started to get stuck. But we described the core all night and learned some new things – like what kind of rock is under the ice. Since almost no rock sticks up above the ice, this is how we tell what is underneath. So every hole, even a short one like this one, has a story to tell.

We’ve since moved 84 nautical miles to place where we are sure there is no channel. The water is deeper but we are much more likely to achieve our main objective of seeing back into a time when Antarctica was ice free. So, we are all still excited and we are also trained as it was the first time the entire team of 30 scientists worked together with the staff and technicians on the ship to recover and describe the core.

Here are a few photos. The Albatrosses around the ship are amazing. They follow us everywhere.

Black-browed Albatross from the deck of the JR Expedition 318.

Expedition 318 scientists waiting for the first core.

Sakai-san, my roomate aboard the Joides Resolution Exp 318. He is an expert in Radiolarians, a really cool microsfossil.

ABOARD THE JOIDES RESOLUTION, OFF THE COAST OF WILKES LAND, ANTARCTICA– Finally, after 11 days of transit, we are spudding into our first drill site off the coast of Antarctica. It’s 3AM and we have just finished putting nearly 4 km of drill pipe together and hanging it from the derrick in the photo. The pipe is suspended only 5 meters above the seabed. We are getting ready to retrieve the first section of a sediment core ever taken from of this site, Wilkes Land!

The JR derrick. Currently, it’s supporting nearly 4 km of drill pipe.

The whole ship is abuzz with excitement. Everyone is awake to see what we will get. We will drill up to 1400 meters below the seafloor here over the next 18 days. Will we get back to sediments deposited when Antarctica was lush and green? It seems likely at this point, but first we will examine the age and makeup of the sediments right at the seabed. They should reflect the current glacial nature of Antarctica and maybe even tell us about changes in Antarctica in the recent past, the past few thousand years. We use special tools to collect these soft upper sediments – an advanced piston corer that shoots into the mud in 10 meter sections. This very first core will be on deck in only 30 minutes. We’ll send a special 2 minute video clip for the blog to capture this historic moment. Leg 318 begins in earnest today!

The JOIDES Resolution.

The JOIDES Resolution.

One of the most sudden and dramatic climate changes to impact the earth occurred some 30 million years ago: This was the transition from a Greenhouse World, when ice caps were largely absent and the earth was much warmer, to an Icehouse World with extensive polar ice sheets, exposed land along the continental margins, and glaciers that periodically extended into the lower latitudes. Investigating this climate switch, thought to be mediated by changes in atmospheric carbon dioxide concentration, will help scientists better understand what triggers vast environmental changes that fundamentally affect life on earth.

Ground zero in these studies is the area just off the coast of the East Antarctic Ice Sheet, the world’s oldest and largest polar ice field. By drilling into deep ocean sediments along Antarctica, scientists hope to uncover the earth’s climate history from a time when East Antarctica was largely ice-free, and to investigate its transition to the glacier-covered continent we know today. Investigating this history, and the effect of increased carbon dioxide and other greenhouse gases on polar ice sheets, will help fine-tune computer models and lead to a better understanding of the climate changes we’re experiencing in the present day.

An example of a cross-section of a sediment core.

Co-chief scientist Carlotta Escutia led an international team of marine geologists and climate scientists aboard the JOIDES Resolution, one of the most sophisticated ocean-drilling ships in the world. They set off from New Zealand in early 2010 to drill cores and collect sediment samples off the coast of Wilkes Land, a region of East Antarctica south of Australia that’s thought to have been the final area to become ice-covered during the last great climate transition.Marine geochemists Rob Dunbar and Christina Riesselman from Stanford University reported from this history-making expedition.

Planned drilling locations (yellow markers) for the IODP Wilkes Land Expedition.

This one-of-a-kind airplane features an array of instruments for studying the East Antarctic Ice Sheet and the bedrock below: radar, a magnetometer, laser altimeters, and a gravity meter. Skis allow the team to land nearly anywhere in Antarctica if necessary.

The specially-quipped C-47 aircraft is designed to conduct long-range airborne surveys in Antarctica and Greenland.

The East Antarctic Ice Sheet is the sleeping giant of the cryosphere: it covers more than 95% of the Antarctic continent and locks up more than 60% of the world’s supply of fresh water. Considered much more stable than its smaller counterpart in West Antarctica, scientists are turning more attention to studying the history, structure and dynamics of this mysterious icy world. Instead of taking the stability of the ice sheet for granted, scientists from many different countries are digging into East Antarctica’s climate history to help predict how this vast ice sheet could respond in a warming world.

Graduate students Dusty Schroeder (foreground) and Jamin Greenbaum (rear) monitor instruments during a survey flight.

As a member of a research group at the University of Texas, Austin, Jack Holt participated in a multinational project called ICECAP to survey an enormous, unexplored part of the East Antarctica Ice Sheet. Building on their research experience of the last two decades, the UT team employed a ski-equipped aircraft outfitted with unique instrumentation, including an ice-penetrating radar capable of mapping the surface, internal layers, and the bottom of the ice. Other instruments revealed information about the density and type of the underlying rocks. The aircraft was also fitted with a suite of secondary instruments including specialized GPS receivers and cameras. One of the goals of ICECAP was to find the oldest ice on the continent, the site of a future ice-coring project to unlock climate records that go back a million years.

Data from the ICECAP project will help scientists understand how the East Antarctic Ice Sheet, with its enormous supply of fresh water, might react to changing environmental conditions. The ice in the target area is generally over 2 miles (3.5 km) thick and the bedrock lies mostly below sea level, making this ice potentially more likely to make a rapid contribution to sea level rise than the ice sheets in Greenland or West Antarctica. But the largely unknown continent buried beneath is also important for forecasting how the ice might respond to a warming world: The slope and roughness of the ground, the presence of water (including subglacial lakes), and the type of rocks are all factors.

ICECAP season 1 flight lines.