And we all roll merrily on...

Leaving the ice wasn't and isn't the end of the ANDRILL project, or the SMS scientific effort.  It is only the beginning of years of work based on this core and the other information collected in our intense 2-3 months on the ice.  

Much of the team is meeting again this week here in Tallahassee, Florida at the university to review what progress each of the discipline teams have made in analyzing their samples, visit the core again (like a long lost friend), select additional samples to be taken from the other side of the working 1/2 of the core, the one we didn't touch while on-ice, and to make plans for future collaborations, meetings, and drill hole proposals. The heat,

 humidity, trees and insects make it a very different environment

 than where we saw each other last.

The primary reason we are meeting here is that Florida State University houses the Antarctic Core Library.  Every sediment core that has been drilled in Antarctica (remember there aren't that many) is stored here in a climate controlled room.  We suited up in heavy coats and suits to go in to take a look.  

Looking at innocuous rows of shelves and boxes, it felt a little like I was peering into the government warehouse at the end of the first Indiana Jones movie - who knows what is in each box!?  Only I do know.  I know what the depth numbers mean, I recognize the acronyms of the projects and know where each one was taken from.  I know exactly how much trouble, sweat, teamwork, and expertise each box represents.  And I know what kind of 

information we can learn from them.  

Thanks ANDRILL!  Your big picture vision of a multi-national, interdisciplinary team has made an incredible difference to me, the other ARISE educators, and everyone we have had a chance to share the experience with!

Curious George and the Penguins

I last left George back at the dorm with the instructions, "Don't get into any trouble while I'm gone."  Unusually enough for George, he has stayed out of trouble!  Such a well behaved little monkey.  

As a reward, I arranged for him to visit the local Cape Royds Adelie penguin colony with a friend of mine, Jean Pennycook.  She works with Dr. David Ainley monitoring the long-term effects of changing climate on the penguin colony.  Her trip there was delayed until after I left the ice, so George will stay with her for awhile, then come back to New Zealand with some of ANDRILL's scientists who live in Christchurch where I can pick him up before heading back home to Alaska!

When I got to see the photos from George's trip, I was amazed to see how friendly the Adelies were to George.  I'm glad he decided to come back home with me rather than stay with the penguins.  It is probably because he doesn't like to eat fish!

It certainly looks like they had fun!  Huge thanks to Jean, Louise, and Kari for introducing George around and taking his picture for me.  Thanks to everyone who sent comments and requests for places for George to visit on this trip.

Slice it Thin

The purpose of making thin sections is to create a thin, polished slice of rock 30 microns thick attached to a microscope slide that can be examined under a polarizing microscope to identify the mineral composition of the rock.  

The process starts by attaching the rock sample to a glass microscope slide.  Below the rock is being attached against the frosted glass side of microscope slides with epoxy on the pressure jig that provides even pressure and a consistent thickness of epoxy.  If samples are very porous or crumbly, they are first saturated with epoxy, sometimes using vacuum impregnation.  There can't be any air bubbles or unevenness between the rock and the slide surface.  It takes a couple of hours for the epoxy to cure on the hotplate where the jig rests.

The next step is to cut the rock samples down as soon as possible after the epoxy sets, especially large samples as they cool more unevenly and could generate enough force to crack the glass slides.  The excess sample is trimmed neatly off with a vacuum swing arm on a rock cutting saw (below).  The glass slides provide a good seal on the vacuum plate, the arm allows the new cut to be parallel to the surface of the slide so the finished product will be exactly the same thickness all over.

Next the slides with thicker-than-final rocks firmly attached are placed on the lapping machine to be slowly polished down to the final exactly-30-micron thickness.  A vacuum system again holds the smooth glass slide against the weighted chuck, holding the rock sample down to the grinding surface.  The grinding plate has to be absolutely flat or the finished slides will be uneven so Steve constantly monitors the process, moving slides and arms around.  In the picture below you can see one vacuum chuck loaded up with slides, ready to go on the lapping disc seen behind.  Various sizes of abrasive grit slurrys are used to provide the grinding action, getting finer and finer as the process comes to a close.  Using a fine grade grit at the end is important for optical quality work.  The final few microns are polished away by hand.

Steve Petrushak is an artist and miracle worker.  Samples so crumbly that we could barely (or couldn't)

 get them out of the core in one piece, he manages to create perfect thin section slides.  The ANDRILL team is lucky to have him!  He examines each finished slide to make sure it is ready to be used to identify the core's mineral components at that sampled depth.  He has requests for 600 thin section slides this season, which works out to about 50 every two days.  He is currently managing around 15 every day so will be continuing work after some of the team has left the ice.  To work in this field he says is useful to have some background in mineralogy, optical geology, and crystallography, as well as a good mechanical feel. 

The finished product!

Eye to the Microscope

On the next microscope over, Dr. Kari Bassett spends much of her time examining and describing thin section slides like the one shown twice in different lights below (tune in tomorrow for all the details on how these thin slices of rock are made). Even though we look at them both under a microscope with different lights to learn about them, one major difference between the thin section slides and the smear slides I am working with is that the thin section is a slice of rock of known thickness - 30 microns.  Knowing the thickness of the slice allows scientists to use light accurately identify the minerals that make up the rock. A "rock" is anything made of multiple minerals. 

On the first look at a slide, the aim is to categorize the compositional type of the rock the slice was taken from (e.g. mostly terriginous) and get some grain size data.

When Kari looked at the slide above (plane polarized light on the left, cross polarized light on the right) some of the things she noticed were the two large chunks of material included in this rock.  In plain polar the one on the left is transparent and yellow, in cross polar it is black and opaque (can't see through it) - this means it is composed of glass.  How on earth does glass get into rock?  Volcanoes!  This whole area is tectonically and volcanically active.  We even have an active volcano, Erebus, on the island we are living on.  The bubbles in the glass indicate that the eruption occurred in cold conditions, the frothy lava didn't off-gas entirely before solidifying. Since it is only a small piece of volcanic glass, it has travelled to the place where it was incorporated into the sea floor.  The chunk on the right side of the slide, opaque and black in both types of light, was changed by the weathering process into pyrite or magnetite.  Overall this is an iron rich sample.

Even if you don't have one of the vital handbooks for checking on what you are seeing under the microscope, like The Colour Atlas of Rocks and Minerals in Thin Section or Microscopic Identification of Minerals, take a look at the paired images of a thin section slide below and describe features you notice.

Of the many things you might notice, look at the two grains that are brownish tan in the plain polar light on the left.  These demonstrate why mineral identification of grains needs both plain polar and cross polar examination.  When you look at the same two grains under cross polar, one is still brown and transparent, the other has turned black!  That one is glass, the other pyroxene (also a volcanic mineral).  Like the pyroxene in this slide, some minerals look the same under either light, others change a lot.  Either way, it tells us about what type of mineral it is.

What types of things can you think of that you need different sources of information about to be sure you are accurate?  What might be a good analogy for thin section mineral identification? 

For more on thin section identification, check out this online guide.

Boxing Day

Like me, you may never have wondered where all the boxes for the core come from.  They are just part of the scenery!  No one nips out to the corner store to buy them.  Today we had to build them ourselves :) 

A major part of planning for any science team heading to Antarctica to do research is figuring out to the last item what will be needed to conduct their science work for their whole visit.  There are some things that are common to all science teams that NSF brings in and maintains at Crary

 lab: glassware etc. and even some larger pieces of equipment.  For teams that require specialized 

machines, computers, tools or supplies, they figure out what and how much they will need, then pack it up and ship it to the folks at Raytheon, well in advance of deployment.  

Don't miscount - you might end up in the embarrassing position of having brought down too much or too

 little.  Too much and you wasted precious cargo space.  Too little and you might not be able to finish your science work.  Logistics pros from Raytheon schedule the cargo in and

 out of all USAP sites, planning so that the available space is used to get things there just in

 advance of when they are needed, as there isn't too much storage but the science isn't being held back either.

Box party in the lab!  Everyone comes and 

pitches in to turn huge piles of flat waxed cardboard into core boxes.  Today we made boxes for HQ (3 sections of core per box) and NQ (4 sections of core per box) diameter core.  These boxes are a little over 1m long.  This stuff is tough.  Thick waxed board has to be painstakingly bent at the dotted fold lines to make the right shape.  There is a lid, base and insert for each box.  Making boxes takes time but there is lots of teamwork and music, so we have fun.  After, we have to scrape all the extra wax off the tables and floor - not as much fun.  

This is our second box party, hopefully we won't need another before we are done.  How many boxes do we need?

Just think about this example: for 1000m (or 1km) of core, if a third is drilled in each of the 3 sizes it would make 333m of PQ, 333m of HQ, and 334m of NQ.  How many boxes would we need?  

(hint: each PQ box holds 2m of core, each HQ box holds 3m of core, and each NQ box holds 4m of core.)

Smear slides galore!

My main job with the sedimentology team for the last several weeks has been taking photographs in regular light and cross polar light (see the pictures at the bottom of this blog) of magnified smear slides from the core. Brad Field on the night logging crew makes at least one smear slide from each meter of core (we have drilled 1138.54 meters of core = at least 1139 smear slides) and more from some intervals of sediment. A smear slide is made by taking a little scrape of the sediment with a tool (toothpicks and dental tools are both used) and then spreading that sediment sample thinly on a glass microscope slide. A clear fixative is added to the slide to hold the sediment in place and then a cover slip is attached. Each smear slide is labled with the depth in the core from which it was taken.

These smear slides are used initially by the night logging crew to help with the description of the core and to give the initial compositional name to the sediments. The sediment might be mostly terriginous (sediment from the land), or perhaps have more volcanic or biologic origins. The smear slides also give the team some information about grain sizes. This may make the difference in the name given to the sediment in the formation. For example, diamictite vs sand with pebbles. To be true diamictite, the sediment must have all three grain sizes, gravel, sand and mud, without any one of those size classes, that section of rock will have another name. This information is part of Chris Fielding's core summary shared with the whole group every morning.

The photos I'm taking are primarily for archival purposes. There are scientists working with this information all around the world and most will never travel to Florida to view the actual core itself. The images taken by the teams here are placed on a shared computer drive that everyone in the project has access to. This makes sharing the samples much easier than having to physically send the one set of smear slides to different countries....it also means that we only need one set, because everyone can use it, we don't need one set for each scientist. With 1200 smear slides, you don't want to make lots of sets! It is also part of our data set, the information that core description and characterization is based upon needs to be accessible to everyone in the team.


Compare the two pictures of the same microscope view of smear slide (at 10x). What observations can you make about the various grains with the two kinds of different lighting?

Following the tracks

In the roads around town, there are many interesting tracks made by the wide variety of heavy equipment and all-terrain vehicles used here. The picture above shows the tracks and some of the vehicles they were made by.

It isn't always easy to match them up. I still haven't seen the vehicle that made these:
Based on the marks it has left in the snow and dirt, I can guess what the tire or tread surface that made it might have looked like and I can get an idea about the path it followed as well as how large/wide a vehicle it might be.

Similarly, we can use the tracks and paths left behind in the marine sediments of the core by small animals to figure out what type of animal (often worms) might have left them, their size, how they were moving or behaving, and perhaps how many were active in an area (population). These sections of sediment that were disturbed by biological organisms post-deposition but pre-consolidation (after the sediment settled but before it turned into rock) are described as being bioturbated - mixed by living organisms. The most important information that the ANDRILL project gains from these trace fossils are from those that can be used as index fossils - giving a date or date range for the rock in which they appear. Many of these characteristic trace fossil types have specific names even though we don't know the exact species or genus that created it. One type, called escape traces or Fugichnia, are created when a shallow burrowing, near surface, or surface marine animal gets burried suddenly under a quantity of sediment and has to dig furiously for the surface to survive. (Look up "trace fossils" or "trace fossil classification" for more information about these fascinating fossils!)

In the photo of bioturbated sediment in the core above and to the left, see if you can find burrows and other evidence of the movement of organisms through the sediment. What might you be able to tell about the organism involved?

Notice what the movement of organisms has done to the layering of the fine sediments. Compare it to the picture on the right of soft sediment deformation caused by physical or mechanical stresses experienced by the sediment over time. What similarities and differences can you find?

A penguin a day...

Even though I have only seen one distant Adelie and no Emperor Penguins while here at McMurdo, there are enough penguins around the base to make up for it! Everyone has the same fixation. There are penguins at the water plant,

penguins at the Field Safety Training Program garage,

penguins collecting library books,

and penguins at the store.

They even have a house,

and tell us what to do!

There are penguins at the hospital,

penguins at Scott's hut,

and, of course, the occasional kiwi.

Do you see what I see?

When I was in Tanzania, I found out a curious fact. When I am scanning the bush around me, I don't pick up leopards or other cats at all. I notice birds and ungulates, am often one of the first ones to see them, but a cat would have to be chewing on my leg before I can find it. Possibly this is because I spend most of my time in Alaska with half an eye on the look out for moose or bears and I am always looking for a new bird. My search image is well developed for these types of shapes and motions....but I've never spent any significant time in an area where it was important to notice large cats - or for that matter, snakes, which I've nearly stepped on at times.

Very similarly, the scientists looking at the core bring their areas of greatest experience with them when they look at the core. A volcanologist will tend to notice igneous features while, for a sedimentologist, the most obvious parts of the same section of core will be the layering and texture patterns of the grains of sediment. We all do this to a greater or lesser extent - we tend to be drawn to and pay more attention to the things that interest us most or that we are most familiar with.

One of the great strengths of the multi-disciplinary nature of ANDRILL is that everyone brings their special area of interest to the endeavor and then shares their ideas and observations with others who have very different starting points and backgrounds. The scientific discussion then involves exploring the ways in which the data might fit together to answer the big question of what was happening in this area of Antarctica in the past. The final explanation that is rendered must accomodate all data from many science disciplines, making it a much stronger statement than one coming from just one viewpoint.

The interpretation of the SMS sediment core needs scientists from both tectonic and environmental perspectives. For example, evidence in the core for deeper water environments may indicate an increase in sea level caused by ice sheet melting or it might indicate rifting and subsidence in the plates of the area - or more likely, a combination of both. We are looking in the core at a record of sedimentation and erosion. Sedimentation happens in where there is both space for sediment to accumulate and sediments in the area to fill it. We need a complete picture of both the tectonic and environmental factors that might be creating the sediment and space for it to fill in order to understand what was happening here in the past.

Take a look at the picture at the top and see what animal you notice first (there are two). What are the things you focus on in an outdoor environment, what do you see first? How about in indoor environments? How does what you notice differ from what someone else in your school or family notices?

Taylor Valley by Helo

Last week at this time, I was sitting at the window seat of a Bell 212 helicopter with my jaw on the floor as we flew through some of the most magnificent scenery I've ever seen. The sun was out, there were fluffy white clouds to give a bit of definition and the wind wasn't bad enough to bounce us around very much. A perfect ride!

Taylor valley, unlike its neighbor, Ferrar, has no single glacier filling the entire valley. There are side glaciers coming into the valley, like the Commonwealth glacier where we stopped to hike, but most of the main valley floor is a series of small lakes or dry ground. The upper valley is where the Taylor glacier is located, and we flew over the vast area where the Taylor and Ferrar glaciers go side by side. At some point in the past, the mouth of the Taylor valley was blocked and the whole thing filled up with water. You can see the remnant shelves left around the edges of the valley showing at least two different water levels.

What landform features do you see in the photos that were created by glaciers? By wind? By flowing water?

Signs of Spring

When we first arrived, low temperatures hovered around -30F without windchill. As weeks go by, those numbers keep creeping upwards- now nearly always in the positive. Recently any day that is sunny has created puddles, dripping eaves and icicles, and muddy spots. I even saw some joggers the other day.

Another sign of spring is the return of our skuas. These scavenging birds are very effective at finding food resources, they know that Building 155 is where the galley is located, anyone carrying out food wrapped for later has to be prepared to keep it from the birds. The first skua of spring was actually spotted flying past on the 4th of November but they didn't really move in to town until a week or so after that. Now they are sitting boldly in the middle of the road or parking area most mornings.

The hard packed snowberms that surrounded the buildings and encroached on the roads when we first arrived are mostly gone now. It seems like a strange time to have Thanksgiving, the sun and melting make me think of Easter and spring instead?

What signs of changing seasons do you look for or notice first?

Educator Night at Mario Zucchelli!

American Night at Scott Base is a Thursday night tradition where shuttles run from McMurdo to Scott and back for most of the evening and Americans are welcome to visit the Kiwi station. Kate, Graziano and I did the Italian & American version when we had the good fortune to be invited to visit the Italian station up the coast - Mario Zucchelli (formerly Terra Nova). We grabbed our ECW and overnight things in about 20 minutes and hightailed it to the airfield. We rode north in a 14 seater souped-up Twin Otter run by Ken Borek Air Ltd, a Canadian company under contract for smaller scale Antarctic air transport between many nations' stations in this area (2-8 hour flight radius). Also on the flight with us were a few Italian base staffers, the new French station manager for Concordia (a year-round joint French and Italian base at Dome C on the polar plateau) and a Polish-Canadian pilot catching a ride. Antarctica is a wonderful model for international cooperation, everyone is working towards similar scientific or logistical goals under extreme conditions.

The hour and a half flight was a fabulous flightseeing opportunity as we hugged the coast of Ross Island, then crossed sea ice in many forms, a glacial ice tounge and two polynyas (large ice-free areas). The patterns created by the fracturing and crushing, melting and refreezing of the ice were ever changing and gorgeous. I was especially fascinated by the new ice where fractures had split apart and then pushed over and under each other, creating a zipper effect.

Mario Zucchelli station is situated on a granite peninsula with wonderful views in every direction. We were warmly welcomed, fed an amazing dinner of clam pasta, breaded sole and soup, and then given a tour of the station. Much of the main station building is made from connected container vans and is a cheerful blue and red. Kate and I found our names on the door of our dorm room, and very cozy bunk beds inside with fluffy feather comforters. We didn't spend much time in our room, as we had such a short time at the base, we got out and did as much walking as we could. The weathered granite with exceptionally large crystals around the station was very different from what we see on our volcanic island home, or in our visit to the Dry Valleys. After a great breakfast we took off for McMurdo, far too soon. A HUGE THANK YOU to Roberto, Jean, Lucia, Guissepe, and all the other folks at MZ who made our quick visit so special!

How many countries have Antarctic or Sub-Antarctic Stations? How many are seasonal vs year-round? How many people work there? Can you find pictures of what some look like?