Final blog, 2013 expedition

On 16th January a Twin Otter arrived at our airstrip. John and Malcolm flew immediately to the site of the subglacial Lake Ellsworth project to see if the radar could pinpoint problems associated with the cavity and the decision to abandon the drilling to the subglacial lake at the end of last year. It seemed a good opportunity to use the appropriate radar while it was so close. Late in the day the plane returned and flew the rocks samples plus David and Stuart to Sky Blu. After one night in a much warmer tent than on the outward flight, we took the DASH-7 to Rothera and the glory of a shave, shower, salad to eat, and a beer in the bar. The remaining members of our party came in during the next two days, all experiencing the same delights at Rothera. We have left a depot of everything possible at the camp site for next season, including food, three skidoos and fuel.

Life at Rothera is full. To see wild life is a delight and reminds us of how much we missed it in the interior. We are surrounded by Weddell and Crabeater seals, Adelie penguins and see Minke and Humpback whales and fur seals. The rock boxes were stored in our science cubicle and the first surprise was to find them standing in pools of water the next day. The small cracks had allowed them to fill with snow while in the field and we had to empty and dry them all out, repack them with Bills of Lading etc. ready for transport by ship in March.

A highlight for us on Monday was our science presentation to a packed room. We covered the rationale for the project and each of us spoke about what we actually did in the field. Scott and Malcolm ended with their video of the project – a fine light-hearted slant on the science. It was good to have the opportunity to talk of our work and the discussions afterwards over beer showed that many were interested to hear of our experiences. It was a good way to remember a field season in which, as a result of good support and fine weather, we achieved more than we had hoped. The flight home via Punta Arenas will give us the chance to fine tune our plans to analyse and publish our results.

So, finally we would like to thanks everyone who has supported the project, both in the early days of conception and preparation, but also our families, NERC, colleagues and especially all those in Antarctica who have helped make it possible.

And did the West Antarctic Ice Sheet disappear in the last interglacial? Probably not.

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Ellsworth Blue-ice Project Blog 11

11th January, 2013 and it is two months to the day since we left home in the UK.  It is also the last week-end before uplift and we have spent the last week finishing the science programme and preparing to leave.  The weather has reverted to bright sunny days with gusty winds of 25-30 km per hour blowing drifting snow around the tents. The highest temperature each day is around -10 C so, bearing in mind the wind, we are wearing a lot of clothes.

Talk is increasingly of what we are looking forward to when we get back to Rothera base. Top of the list is a hot shower. I think we are all shocked to realise that we have not washed our hair since 22nd November and that we have relied on a few wet wipes for all ablutions since then.  The thought of shampoo in a shower of hot water is almost a fantasy.  Next on our list is a beer in the bar, fresh fruit, food that you can chew, standing up straight indoors, and a flush toilet instead of a pee-bottle inside and pee-flag (bamboo stick) outside.  A final item on the wish list is a new pair of socks for Scott!  Socks excepted, it is strange how we have reached an equilibrium and that we no longer notice our state of hygiene.

The final week of science has been used to fill gaps, such as securing cosmogenic samples from high-elevation bedrock, installing a micro weather station to run for a year, measuring the altitude along the blue-ice margin, and re-surveying all the 90 stakes recording ice flow in order to see if there are any trends after two months.  We also excavated a trench across a moraine ridge to check that there was a debris band there.  There was!

A highlight of the week occurred on the day the weather changed to give us strong winds.  Cirrus clouds formed as the winds blew over the mountains producing constantly changing patterns of waves, stacks of lenticular discs and funnel shapes like chanterelles, all brought to life by opalescent patterns around the sun.

Over dinner of our usual packet of Pack ‘n’ Go, we estimated that each skidoo has gone about 1200 km, making a total for the four of nearly 5,000 km, mostly commuting to and between the mountain groups.  We have collected 280 cosmogenic samples, each weighing an average of 1.5 kilos, and aimed at dating a particular event.  They now require two years’ work to process.  We have run Differential Global Positioning Surveys (DGPS), accurate to cm, for some 50 km. We have installed 90 stakes in order to measure glacier flow that will be re-surveyed next season.  We have over 15 km of Ground Penetrating Radar (GPR) over the ice and moraines, each one measured with a 3-second stop every 10 or 20 cm!  We have high-resolution laser scanned maps of the main moraine system as well as of mountain fronts in six different locations.  The successful flight of the remote-controlled plane has given us vertical photographs of the vital details of the surface structures in the main moraine system. 

So what does it all mean? In a nutshell we can now begin to answer two main questions of process and evolution that underlie much of science, namely: What’s happening now? and What happened in the past?  Applied to our project the questions are: What processes form blue-ice moraines? and How do they evolve over time?   The link between moraine forms on the surface, structures in the underlying ice, and measurement of changes over the course of a year helps reveal the process of formation.  The geomorphic mapping linked to cosmogenic dating will allow us to track the evolution of the moraines over Ice Age cycles and indeed over millions of years. 

What are the implications for the Antarctic Ice Sheet?  Well, blue-ice moraines certainly provide new insights into ice-sheet history and there is a lot to be gained from their study.  So, now our thoughts have returned to the original question: Did the West Antarctic Ice Sheet disappear in the Last Interglacial?  We are confident that we will be able to answer this convincingly.  We have our hunch but must wait for the dating before we go public.

Ellsworth Blog 10

5th January and time to take down the tinsel and Christmas decorations! The New Year continues to bring clear weather with temperatures generally around -10 C and lots of sunshine. One recent day was exceptionally warm and actually saw us pulling the radar while stripped to our base thermals, a rare occurrence at 80 degrees South.
Work continued over the festive break and now our attention is on the more distant massifs of the Independence Hills and Marble Hills. Each involves a commute of over an hour and the journey is very different. In the case of the Independence Hills two people travel on backward-facing seats on a Komatic, a sledge based on a Greenlandic Inuit sledge. We go over a long snowdrift via a pass in the Patriot Hills. Two skidoos pull the sledge up and the backward-facing view is special. It is like taking off in a plane and seeing the horizon widen and spread out in front of you. At first there is a view of an ice slope, then of the glacier surface, then nearby mountains and finally the whole vista of the southern Ellsworth Mountains – all in a minute or two. Skidoos are then attached to the front and back for the descent onto the next glacier. Since the journey to the Independence Hills is into the prevailing wind the skidoos travel parallel to the alignment of the sastrugi. The journey to the Marble Hills is across the alignment of the sastrugi and is slow and bumpy; we tend to ride with driver and pillion for comfort and security.
The Independence Hills are partly volcanic and we work on a complex of moraines overlooked by magnificent cliffs towering some 500 m above us. We have discovered that the flow of the glacier in front of the cliffs changes direction as the overall ice thickness changes during glacial cycles in response to sea-level changes. The radar work shows that some of the moraine is trapped in an embayment as the ice moves first one way and then in the opposite direction. So we are hopeful of being able to date the oldest material to see if it survived the last interglacial warm period.
Marble Hills continue to impress. At a new site the initial surprise is a hole. You step off the skidoo at the main ice margin and then walk DOWNHILL for a vertical distance of 140 m. The shape of the topography and the winds are able to keep the basin clear of ice. Anywhere else in the world and a hole like this would contain a lake or be filled in with gravel. The climb back to the skidoos at the end of the day with rucsacs full of rock samples was hard. We have made good discoveries in the Marble Hills. We have found buried glacier ice beneath deposits at altitudes about 300 m above the present ice and at higher altitudes are some of the oldest deposits in the region. It will be interesting to find out how long a history we are unravelling. Our instinct is that the ice sheet has changed in thickness to a certain degree but that it has persisted for a long time even by Antarctic standards. The cosmogenic dating should help enlighten us.
Today there is little wind and Stuart was about to fly his remote control plane with a camera to take vertical photographs, the whole flight being pre-planned with GPS. Andy and I had just installed a small met station on a pole drilled into the blue ice and we saw a plane in the distance. At first we thought Stuart had had great success but it morphed into a Chilean Hercules plane, probably checking out their abandoned base which is now largely beneath snow. Inspired by the Hercules, Stuart got his plane airborne and has successfully got vertical photos of our detailed test site. Great news!

Our uplift date back to Rothera is 14th January so we are busy tying up loose ends in the science programme. Malcolm and Scott are beginning to prepare for our departure and plan the storage of camping equipment, skidoos, etc so that the latter survive the winter and can be re-discovered next year. The suspension of one of the skidoos gave out today and Malcolm and Andy are replacing a major part just now. We do not want to ship ou t a heavy skidoo if we can avoid it.
A few more days of good weather?

Ellsworth blog 9

29th December and we still experience mainly cloudless skies with winds of varying strength and temperatures around camp rising to about -6 C. We celebrated Stuart’s birthday before Christmas and then the day itself. Christmas Eve was devoted both to science and to moving the communal tent.  Why bother with the latter?  Well, the snow under the tent had melted wherever it was unprotected by boxes.  Thus the boxes were on pedestals of ice and the living spaces had melted to form craters.  So we had lots of headroom in the tent (!) but could not move without sliding down into a hole.  Digging out metres of snow from the extensive valance took all morning and then we had to move the generator tent to nearby.  All is fine now with less headroom but a flat floor.

Imagine our Christmas dinner.  We feasted on shallow-fried marinated duck with a cherry sauce created by John.  Scott and Malcolm dug into our deep freeze in the snow to reveal and then cook treasured freshly -frozen sprouts, stuffing and roast potatoes.  We opened and enjoyed a bottle of Gato Negro red wine. The meal ended with mulled wine and Christmas cake specially cooked for us by Caroline back in the UK.  You must be imagining the white table cloth, the low lights and the tinkle of glasses, as we did.  We managed to forget that the meal was in a plastic cereal bowl, the wine in a plastic mug and that the table was littered with its usual load of partly used containers of treacle, jam, tea, primuses, pots and pans.  Thanks to the many of you that sent greetings to us and helped us feel less remote on the day. But it was sad to hear of the problems of the Lake Ellsworth project on that day and our thoughts are with them and we wish them good luck next year.

Meanwhile, we are close to finishing the main survey of the Patriots.  The radar is producing excellent results and revealing what is happening within the glacier and helping make sense of the features on the surface. Even I (David) have got involved in high precision work by fixing the location of boulders from a particular cliff source with a roving GPS.  For someone who might previously have simply written that limestone boulders show a particular direction of ice flow, I spent two days, along with Andy, measuring the precise location of over two thousand boulders!  All I remember is a disemboweled voice repeating at each boulder: Observation Stored.  The resulting map will certainly show the direction of ice flow at to within cm.

We have begun work in the adjoining Marble and Independence Hills. Stuart is using the laser scanner in the latter to record rates of weathering on some spectacular cliffs and already has great images. Yesterday we all participated in a hard day to the Marble Hills which started at 10 am and didn’t finish till after midnight. It was to help Andy drill a rock core 2m into marble bedrock into what seemed the highest and most exposed hill in the area.  Andy says the exposure is to minimize the possible impact of snow cover. Hmm!  We carried up to the summit the drill motor, bits and extension rods, fuel, 60 litres of water-based lubricant (!), pumps, angle grinder etc.  BUT it was windy and cold on the top with a temperature below -15 C and a strong wind with gusts literally blowing one over as well as removing drilling rods and rucsacs.  The idea is to get cores from different depths which some magic analysis can transform into weathering rates over millions of years.  We battled with icing problems ruefully reminding ourselves that this drill had never been used in sub-zero temperatures before. There was a slushy mud of marble everywhere on clothes, sun goggles and beards.  Hands were tested collecting and recording the extracted core every few cm before the wind blew the samples away.  8 hours later in what seemed like a wind tunnel we got good cores down to 1.6 m and Andy declared himself happy.  The mountain top has one of the most spectacular views I have ever seen and the drill company will be amazed at where we were using their drill for inserting fence posts!  I wonder if we will be able ever clean off the marble dust on our clothes.   

 A Happy New Year to all.

Ellsworth 8 – the longest day..

21st December and it’s the longest summer day. Remarkably the sun seems higher in the sky at midnight than it is in Edinburgh at midday on the same date. With continued good weather and sunshine the tents heat up at night and we are too warm in our sleeping bags. The science is going well and this good weather means we can tie up the Patriot work and we have already started work in the Marble Hills.

Several events of note this past week. Scott saw snow petrels crossing the main ridge of the Patriots. This scarce observation just reminds us of how little wild life there is here. It explains how we delight at the stories on the daily sked about elephant seals colonising a bit of Rothera for their own use and the penguins sunning themselves there. One day last week we had a snowfall of diamond dust. The sun shone brightly but the humidity was sufficient for a constant rain of snow crystals all glittering in the sunshine. This and some rime ice was sufficient to coat the blue ice surface with white crystals. Scott and Malcolm even tried sledging on the blue ice! The humid air made it feel cold all day.

We got a visit by a tractor train one evening! It was on a return trip to the Thiel Mountains where it had dropped 100 drums of fuel. The train of five sledges is pulled by a piste machine. There were five people living in a caboose or driving non-stop, carrying empties back to the ALE base at Union Glacier. It was good to chat and to muse that, with the Fogwill/Turney camp, we have had more visitors in this remote camp than would normally occur at home! Miraculously, when they left there was a pile of goodies such as frozen fresh bread and pizzas.

We celebrated Scott’s 23rd birthday this week with a film sent from home. Our present was a full day of radar, 10 cm by 10 cm. He will never forget the day!

We have begun work in the Marble Hills. Scott and Malcolm explored access routes while Andy and I climbed to 1400 m to recce a site for a rock core of 3m. We found an impressive elevated site with amazing views to pyramid-shaped peaks all around. Looking at the cosmo profile with depth is a way of establishing the age of a surface which may have survived for millions of years. We hope to use this approach to date the highest glaciated surface. Meanwhile, with assistance by Scott and Malcolm, John and Stuart have completed a fine suite of radar profiles in the Patriots which show the persistence and structure of debris bands in the ice underlying the blue-ice moraines.

Christmas preparations are in progress. Stuart and Scott have decorations in their tent. I have retrieved my edible present from the deep freeze in the snow to thaw out. And somehow we have brussel sprouts to go with our meal of ??! More news on this in due course.

Sunshine and little wind

The good weather continues and we have had days of sunshine and little wind. We are pleased at our progress on the science and got an extra boost from a visit by a Twin Otter which delivered 685 litres of petrol mainly for skidoo travel. But wonders of wonders it brought a crate of beer, fresh vegetables and fruit, probably from Punta Arenas, and cakes! We are enormously grateful to those at Rothera who have thought of us and taken the trouble to put together such goodies. So morale is high.

People ask what we actually do on our days of science. Well, let’s start with the most exciting task. I think it must go to John’s radar survey. Imagine a chaotic mass of boulders forming ridges and basins extending several hundred metres from the ice edge to the mountain front. Well John selects a line and then gets either Scott or Malcolm to drag a sledge with the radar across the rocks. So far so good, but each measurement takes place every 10 cm! The radar beeps when it has taken a reading and then there are three seconds to move it 10 cm for another. And so on until the transect is complete! No breaks allowed for coffee! Then there is Stuart’s laser scanner. Early days involved setting up reflectors in various locations on the mountain front. Then the survey starts. A typical day starts with warming up the instrument in a thermal blanket so it can operate in the cold. Then there is some sophisticated programming to tell it what to do and in how much detail. You switch it on and leave it to map the mountain front in detail. Apparently you are allowed to sleep while the machine does the work, so you can imagine it is a popular assignment! Then the cosmogenic dating. The trick here is to know which of the multitude of stones on the mountain front to choose and why. So Andy and I have a detailed seminar discussion on every stone and we are on number 142 so far! Since we want to date the last time the ice dropped a stone we must exclude such things as human disturbance (yes even here there are cairns!), movement downslope or frost shattering since deposition, whether it has enough quartz in it, etc. Once selected we label and photograph it and its location in detail, use an angle grinder, hammer and chisel to take the surface layer of rock, and bag the sample. Many details are needed, such as altitude and possible shielding by nearby mountains, snow patches etc. You can imagine fetching out the various instruments and notebooks to do this without losing them in the wind. We have settled for big anorak front pockets containing everything in one place, for example, GPS, notebook, compass, clinometer, sample bags, marker pen, camera, sunscreen, bar of chocolate and gloves.

One huge change with the past is our ability to see films. On special occasions, such as a Saturday, Sunday or the arrival of beer all six of us cluster round a laptop and watch a film, such as The Guard and the Chalet Girl. When the sun is out the tent remains warm till late.

Our strategy on the science has been to study the Patriots in detail and probably do this till Christmas. Then we will move on to the Independent and Marble Hills. What have we discovered – provisionally at least? Well, the mountains have been submerged beneath a larger Antarctic Ice sheet flowing eastwards across the range. We have found ancient blue-ice moraines associated with this and should be able to date the episode. It could be part of an Ice Age cycle or an early stage of Antarctic glaciation millions of years ago. We have found three stages of blue-ice formation at the present ice margin and, again should be able to date these. We have a detailed laser map of the surface and structures of the moraines, almost certainly the best yet achieved in Antarctica or anywhere in the world. We have radar profiles through the moraines showing the depth of ice beneath them and the structures linked to the surface patterns. There is 180 m of ice beneath the biggest moraine! So we are better able to understand how blue-ice moraines form and their wider significance. Clearly there is lots more to do in the field and later in the lab, but so far so good.