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…..

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– What an exciting day! After 2 days on site we have retrieved our first real core. The problem last night was that the seabed was so rocky and hard that it broke our bottommost drill pipes when we hit. We had to trip (pull up) all 4 km of pipe (7 hours) and use a torch to cut off the bent and broken pieces. We then reassembled the whole thing and put a big rotary diamond bit on the end. Now we have core!

First core on the catwalk, Expedition 318.

It’s been all rock and gravel so far – a real surprise because we are in deep water far from shore. We think this is the top of a giant submarine fan, kind of like what you might get at the base of the Monterey submarine canyon. These canyons and channels act as conduits that carry big heavy rocks and lots of sand into the deep sea. But in this case the rocks and sands were carried to the edge of the continental shelf by ice! Well, we get 10 new meters of core every 3 hours or so now and so the work begins in earnest. Who know what lies beneath the rocks and gravel? We’ll find out soon – in this very first borehole drilled in this part of the ocean!

Christina Riesselman, Expedition 318 diatomist from Stanford, waits for the first sample.

Dirt and liquid water, unusual problems in Antarctica.

As is becoming the norm for us, camp put in did not go smoothly. High winds meant that only our high priority cargo got to us but the rest was delayed for a few days until the winds dropped enough for the helicopters to fly with external loads. So for the first few nights, we all slept in one tent. It was a large tent, so we were pretty comfortable. But I had forgotten to include cooking pots in the high priority cargo, so we had nothing to boil water in until we broke open the survival bags. We felt a little silly opening the survival bags just for pans, but making hot meals was much better than eating yet another bag of gorp.

Maybe if the rest of our tents don’t ever get here we could sleep in an ice cave?

Becker camp. The big multicolored tent was all we had for the first few days.

Of course, the high priority cargo did include enough of our science gear that we could work, so despite the winds we started ROV missions immediately. The ice in the crack, which we had hoped would provide easier access to the ocean, was very hard and not as thin as we might have wished. Drilling took hours every day, and lots of muscle. Combined with the hard ice were pockets of thin crust, which led to wet feet for everyone on the team at one time or another. But, the crack did provide a smooth, and nearly continuous, pathway for hauling our gear.

Everything we need to operate SCINI fits in two sledges.

And those two sledges can be hauled by the support team of 5 people.

After finding such unexpectedly rich communities at Heald Island last year, I was not sure what to expect at this site. Even with that, I was surprised – this time, at how little life there was. Anemones were the dominant taxa, with a smattering of brittle stars, sponges, and these mysterious white sprinkles that, at a diameter of 1 mm, we could not resolve the finer details of. We profiled extensively from 130 to 30 m, where the seafloor contacted the shore ice. At 40 m, there was a thick benthic diatom layer, but nobody consuming the plethora of productivity. And oddly enough, the ice was no thicker than 11 m even off the crack, much thinner than an Ice Shelf should be.

Isabelle on the right and Bob on the left give a sense of scale to the McMurdo Ice Shelf. Heald Island is behind Bob on the left.

So, as is also becoming usual for us, our field time led to more questions than answers. Why is the ice shelf ice so thin here? With the thin ice and consequent high light levels, why are there so few grazers utilizing the high productivity? Are the sprinkles biological, geological or chemical in origin? And finally, what caused the salt outcroppings we found on the slopes near our camp?

Isabelle next to a mysterious salt outcropping. We later read that these are mirabilite chunks that have been pushed around by glacier action.

We were very happy that camp pull out was more efficient than put in, allowing us to return to McMurdo in time for Thanksgiving dinner on Saturday night. Though we did have one triwall slingload self-destruct on the return, nothing was lost. And turkey day dinner was a decadent extravaganza of crab legs and chocolate truffles, in addition to the ALL the traditional Thanksgiving fare. We are so spoiled here. Perhaps the contrast to cold gorp dinners enhanced our appreciation, and the presence of good friends certainly added to our pleasure, but I think the meal was a gourmet a treat as any I have ever had. We owe so much to the wonderful folks here who keep us going in so many ways. I hope that you recognize as much to be thankful for in your lives as we do on the frozen continent.

Packing up the triwall prior to it self-destructing on the flight home. We did let Isabelle out before we sealed it.

The helo ready to take the last of our camp gear. Fortunately this time the last flight (for us people) went off as planned.

Farewell to Becker Point.

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!

We began drilling the glacier ice and despite the weather conditions the day started well as we were recovering beautiful, clean, bubbly glacier ice. But soon the borehole reached a small sandy-pebbly layer within the ice and the pace of drilling came to a crawl. Drilling sediment rich ice releases enough heat to melt the ice between the sand grains. When the drill slows down the ice quickly refreezes and makes a sand ice slurry (yes, I referred to it as “crap” in the video) which adheres to the auger like cement making cleaning an arduous process.

The round depression on the top of the recovered slurry core was caused by the down-hole vacuum which assists in removing broken up rock and ice cemented debris created during drilling. Material not removed by the vacuum is hopefully recovered via use of the core barrel as shown in this video. After a few more cleaning runs with the vacuum and core barrel, we were back into clean ice once again!

Early drill and recovery attempts of the buried glacier ice.

Sediment lenses cross cutting through a 30 cm ice core.

The outstanding question is how old is the ice? Ash deposits overlying the ice are dated to as old as 8.1 Ma (million years ago) which would make the underlying glacier the oldest ice yet discovered on our planet. To further convince skeptics that the ice is indeed old, the principal investigators of the grant (David Marchant, Boston University, and Michael Bender, Princeton University) are attempting to date the age of the ice directly.

An in-situ ash wedge in debris overlying buried ice. The wedge is approximately 30 cm across and 40 cm tall. Such deposits can be dated to give a minimum age for the overlying glacial debris.

To understand how this is done we need to go back to when the planet was forming 4.6 billion years ago. Since the formation of the earth, there has been a slow release of gas from the interior of the planet to the atmosphere (i.e. degassing via volcanic activity). One gas in particular is an isotope of Argon. This isotope does not decay thus its concentration is slowly building up in the earth’s atmosphere over time. Atmospheric gas trapped in old ice would have less Argon isotope compared to recently formed glacier ice. The principal investigators will use this technique to analyze the gases trapped within the glacier ice we collect during this field season and determine an age of the ice. If indeed it is the oldest ice yet found on earth, we will have the opportunity to directly measure important greenhouse gases such as CO2 at timescale millions of years back into earth’s history.