Our camp is called Gabbro Hills, despite that we are actually in the Lillie Range, but the rock units are the same as those for Gabbro Hills. We have been collecting samples for three days and have already packed up about 1400 pounds of rock. Today we were especially victorious because we actually found gabbro! In 1400 pounds of rocks, there is only one sample of gabbro, the rock that this area is named after. It has been surprising to not see it sooner. This area is special to the Transantarctic Mountains because it might be the only place with exposed igneous rocks thought to represent intrusives for both pre-tectonic and post-tectonic Granite Harbor Intrusive activity. Finding these rocks is important because the gabbros could reveal something about the source material for all the granite that the TAM is composed of, as well as clues for the tectonic evolution of the subduction margin along the Antarctic craton. For a crude explanation, magma is generated through volatile-release from the down-moving oceanic plate subducting under the overriding continental plate. As the volatiles are released, the crust is melted, and large magma chambers form along the margin. When magma comes from melting continental crust, it tends to be mostly felsic (made up of the lighter minerals), which produces rocks like granite. Gabbro Hills, however, contains more mafic igneous rocks, possibly suggesting that the magma came from a different source. This other source is thought to represent depleted-mantle material, hence its composition of mostly mafic minerals (the darker, Mg-, Fe- and Ca-rich minerals).
The end result is that we have collected a lot of granite. So things are going well. We are surrounded by stunning granitic spires under clear sunny skies in 15-30 degree Fahrenheit temperatures on Le Couteur Glacier. This is an incredibly beautiful place. I doubt that many people have the opportunity to travel across glaciers in a terrain like this where only a few people have ever explored. We were on an outcrop yesterday and spotted about 10 paleomagnetism bore holes likely from the 1995-96 expedition season led by Anne Grunow. Incredible! I do not think I have ever found paleomagnetism. drilling evidence before. Antarctica is a rare environment where the activity of humans remains completely unaltered after years of passing time.
Yesterday we finally left Miller Range. During the morning phone call to MacOps for the updated flight agenda, a seemingly fruitless task every morning at 7AM (and every 30 minute interval following until the flights were finally cancelled), we got the word during the two flights were coming for us. The previous week had left us feeling skeptic that any flights would actually arrive, but at 9:30AM there were suddenly two Twin Otter planes and Evan, our guide, to help us tear down camp. We woke up thinking we would likely be staying another night and by afternoon we were unloaded at Shackleton Camp. I need to shout out for Shackleton Camp. This is a deep field support camp that is established every few years. It was put in last year and will have its final summer season next year. There are six people based there to run all aspects of camp operations, weather observations, field coordinating, cargo logistics, equipment mechanics, and a chef for meals. On top of the skeleton crew, there are two additional personnel (pilot and first officer) for each plane currently located at the camp. There is the perfect amount of infrastructure in place. We were issued a tent each that was already put up, like a clean and warm sanctuary. The galley building is heated with the chef creating delicious warm meals. There are privacy pee holes and toilet shacks. The best part by far was taking a hot shower (though no soap) and putting on clean clothes. So amazing to finally comb out my hair and not smell like the previous four weeks of no bathing. This is the longest I have gone with no bathing. I have been out on excursions many a time, but never where there is no opportunity to jump in a lake or river for rinsing off. We were only in Shackleton for a quick overnight, but it was a super morale booster. Now it is November 30th and we are in the stunning Lillie Range next to Gabbro Hills with camp set up on a pillowy snow-covered glacier. What a life.
About a week ago we were told to be prepared for a camp move on the 22nd. We packed up the majority of our camp the evening of the 21st. On the 22nd all flights were cancelled due to problems with logistical planning in the field office. Then we had two days of cancelled flights from bad weather at McMurdo. Yesterday we had one flight that took one of our skidoos away with the plan to take it to the new field location. The skidoo ended up at Shackleton Camp. Now there are no flights for the weekend because this is Thanksgiving weekend. So now we are three people and the kitchen stuff jammed into one Endurance tent, stuck on a glacier for Thanksgiving, feeling strung along with inaccurate and conflicting field flight info. Everyone else is enjoying a long weekend and the best feast of the year, while we are making spaghetti and frozen meatballs on a Coleman. Needless to say, we are not exactly pleased with pushing hard days to be ready for a camp move four days early only to be jammed into a single tent and told to sit tight for seven days without being able to do any more field work. At least I have had a lot of uninterrupted work time. Though it would be more productive at a field camp galley with warmth and unlimited hot drinks that don’t require shoveling snow and melting it on a propane stove… or the need to wipe off the newly frosted walls so water doesn’t constantly drip down onto my notebook and sleeping bag anytime we turn on the stove…
Today we headed to our southernmost accessible outcrops at Gerard Bluffs. We were wandering through the area and found a mafic pod where we could literally see the hammer marks on the rocks and a remnant of the “fresh” rock piece that would have been sampled by the previous geology group. I suppose I am only assuming these are remnants of a geology group, but I don’t know any of science group who would have been in the Miller Range hammering on rocks. It highlights an interesting question on the future of geology in Antarctica. That is, what is the future of geology in Antarctica?
About 14 years ago, an incredible resource for geologists was established at Ohio State University called the U.S. Polar Rock Repository (http://research.bpcrc.osu.edu/rr/). It is a national facility funded by NSF’s Office of Polar Programs to house field notes, photos, maps, cores, thin sections, and samples from Antarctica, the Arctic, and southern South America and South Africa. Dr. Anne Grunow, curator for the U.S. PRR, is a highly regarded Antarctic paleomagnetist. She completed about a dozen research expeditions to Antarctica during the 1980’s and 90’s. One of her primary goals with the repository was to centralize the samples collected from all previous expeditions. Having just gone through the process myself, I can say that she is trying to give researchers the ability to access Antarctica’s rocks without the necessity for the resources it would take to perform field work. It is quite the expensive endeavor when you consider the flights to Christchurch then McMurdo, as well as flights on the continent to transport people, food, supplies, and equipment. There are costs for the field teams in addition to housing, feeding, and outfitting all the support personnel that make up McMurdo, South Pole, and all the other stations. To instead open your computer, filter through the approximately 40,000 samples currently catalogued at the PRR, select the few dozen samples you want to work on, and then wait for them to arrive in the mail. This is an incredible opportunity! I myself am currently working on rocks provided by the PRR.
Needless to say, the U.S. PRR is a huge asset to geologists, and Anne Grunow is an incredible scientist for coordinating the endeavor. The only side affect is that it has reduced the need for geologists to get into the field as well as weakened any argument for field work in Antarctica. As a geologist, one of my favorite parts is getting into the field. I love traveling and exploring, but what a far more rewarding experience to combine adventure and science. It is somewhat daunting to think that fieldwork may become a thing of the past as we, the greater scientific community, move toward a system with open data and sample repositories. I am all for collaboration, but I think there are strong arguments for collecting your own samples. It enables a greater understanding of the field relationships for the geologic story recorded in the outcrop. All I can say is how appreciative I am to have had this opportunity to collect my own samples.
Where has time gone? It is November 20th and we are wrapping up our rock hunt at this first study area. We have collected a lot of rocks, and I feel super prepared to jump into this research when we return to UCSB. The strange thing is that I have been absent for a month and feel like I have accomplished very little academically for one month’s worth of time. It feels crazy. I have so much to read and study and learn still. I thought two months of field work would result in a moderate amount of free time in the mornings and evenings to work on my ongoing research. Instead, I feel like I am moving at a snail’s pace on just a few pertinent topics.
Outside the struggle with insufficient productivity, we have had a great field season so far. We came in pursuit of lamprophyres. To break it down, these rocks are:
Highly alkaline (meaning potassium-rich),
Volatile-rich (the modal phenocrysts are biotite or amphibole, both with OH, a water derivative, in the crystal structure),
Mafic (meaning MAgnesium + Ferric Iron; usually referencing the darker minerals), and
Emplaced as dikes (meaning they cut into existing host rocks).
The thought is that these rocks may be sourced from enriched upper mantle material and are associated with the closure of subduction zones. These rocks are found in places along the entire Transantarctic Mountains, an unprecedented regional scale to find lamprophyres. They can tell us something about a specific tectonic setting that is not normally recorded at such a large scale. In summary, we have found a lot of lamprophyres. Success!
On 11/10/16, a windy and cold day, Demian’s and my bags fell off the siglin sled as we drove back to camp. In that realization, we failed to grasp the importance of the sample bag having also ripped open at the zipper. About two days after, we discovered that one rock was missing from that day. Since my pack also contained samples from the day, we sort of thought it must have fallen out. Today we realized that the problem was much more significant. Today we found three samples that were lost that day. Since only one sample was unaccounted for, the other two must represent duplicate rocks or samples that were collected as multiple pieces. Just further proof of how irritating the wind is. It is hard to focus on outdoor tasks like organizing samples when the wind is blowing.
Yesterday morning we called MacOps to add items for our resupply request, and instead they told us that a plane we already en route and would arrive in an hour. The communication on Antarctica has been more than lacking in my time here. We scrambled to gather all the retro and transport it to the landing site to send off with the plane. Then we had to make a second resupply request that should have gone with the original request. This led to the organization of our camp move and us being told we would need to be ready for a camp move four days earlier than originally planned. No worries, we have been crushing the field work. We have 140 samples and hit the lamprophyre jack pot yesterday. It would be nice to have more open communication for our own camp move logistics though.
In addition to the field work, I have been using this trip to try to absorb as much knowledge from John as possible. I am still relatively new to hard rock research. I have been working with John in the hard rock realm for less than a year. Many of the field relationships and rocks of interest are new concepts for me. Sure, I took tectonics, mineralogy, and petrology in undergrad. But that was about seven years ago so my current understanding is shallow. I am excited for my research on these Miller Range rocks, but I have a lot of catching up to do. Being in the field has been huge for rocketing my knowledge baseline into motion. John leads us around, tracking down rocks of interest like a weimaraner on the hunt. Then I take a bunch of field notes and spend the evening looking up all the words I didn’t understand and processes involved to gain understanding on why we are doing what we are doing.
This is an important time for me. I am trying to decide what my focus will be. Do I want to become a geochronologist? Or a petrotectonicist? Or maybe a tectopetrologist? Do I want to focus on the petrology of igneous systems or metamorphic systems? These are important questions. I am paving the groundwork for my future. I want to be a professor, so I better make sure I like what I am getting myself into. John has posed an important question at me, “What do [I] want to spend the rest of [my] life teaching?” It’s a hard question. The rest of my life is a long time relative to my life, my only reference point in anything I partake. It’s a sobering topic to dwell on.
Yesterday we had an adventurous skidoo day. It started with a toppled skidoo at our first stop of the day and ended with the discovery that one of the rear suspensions on the skidoo had busted. Today we fixed it. Since it was 20 knot winds blowing heaps of snow, we came up with a plan. We would put the skidoo into the tent where we would all be protected. We cleared out half of the Endurance tent (our main kitchen and work tent) and we dug out the makeshift toilet (installed behind the Endurance tent when the winds ripped the toilet tent to shreds). Then we unzipped the tent from its base and literally drove the skidoo into the tent. We jacked up the rear of the skidoo with rock boxes, unscrewed the back wheel axle, removed the right rear suspension, put on the spare, and viola! We fixed the skidoo! And then we broke a tiny plastic piece that holds the suspension arm stationary in the process. That piece isn’t operation critical, so our mission was a success! Top most ridiculous moment of the season so far.
We have been in the field for just over a week. We were super lucky that the Basler landed on a sunny and calm day. We had about two days of calm before the winds started. They have yet to stop. We took one day off because the winds were blowing snow at a steady 40 knots all day. Today I caught up on typing field notes, downloading GPS points, and bagging and boxing samples.
An average day involves waking up to boil water, putting on all my layers for a 30-60 minute skidoo ride to an outcrop of interest, spending the day hiking up snowy and ice-covered scree slopes, and freezing my fingers while writing down notes and taking GPS points. Then there is the skidoo ride back to camp, cooking supper, drying frozen gear by the heater, crawling into a -40 degree down bag for bed. Then the whole process begins again the next day. Humans are creatures of habit, so it seems like a perfectly normal regime by now.
The strangest part has been the constant daylight. I will wake up early, my eye mask having fallen off, and think the day is started. The clock will then reveal 3:00AM as my frosty breath steams out of the tiny breathing hole in my down sleeping bag. I go to sleep with hot water bottles each night, listening to the gusts of wind knock the guy lines and loose items around camp. Every structure of camp is within 20 feet of everything else. The sounds are slowly becoming normal, but I still get a strange feeling by the lack of other life. I will hear rustling outside my tent, and my first instinct is to think some mischievous creature lurking about for food scraps. Instead it is the creaking of the thick blue ice beneath our camp or the rustling of cold fabric. Yesterday we saw old skidoo tracks in the moraine field heading out to Milan Ridge, then there were wind-torn and forgotten flag posts up on the edge of the plateau, and a lone metal pole hammered down into the blue ice as we returned across the moraine field. Adding to the desolation, there was the tiniest patch of lichen on some rocks. With all the layers I am constantly putting on and taking off, I feel like an astronaut on a deserted planet. The deserted planet of Antarctica.
I have not been keeping a journal. My apologies. I am going to go with it being due to the cold and wind that seem to control much of my routine each day.
Yesterday we stayed at camp. The winds are blowing hard. There was steady at mid-30 knot wind speeds with gusts up to 40 knots. For those who do not know. A knot is a unit of speed common to boat travel (and for some reason Antarctic weather forecasting) equal to one nautical mile (1.852 km) per hour, or approximately 1.151 miles per hour. At McMurdo, there are three weather conditions, and the only only that allows foot travel is Condition III. This is the safest weather, whereas Conditions II and I require special permission for protected transport or no transport at all (respectively). The definition of Condition III weather is: visibility greater than a 1/4 mile, air temperature and wind chill above -75 degrees Fahrenheit, and wind speeds less than 48 knots (that is 55 mph). To reiterate, this describes “good” weather. Ha! For today, you can think of us driving around skidoos in 35+ mph winds. Not that fun, but also not beyond the danger level. For those not very experienced in windy weather, let me give you some perspective. Hurricanes must have maximum sustained winds of at least 74 mph (>64 knots). A tropical storm has winds in the 39-73 mph range (34-63 knots), and a tropical depression has wind speeds less than 38 mph (<33 knots). Hurricanes (northern hemisphere storms) are ranked using the Saffir-Simpson hurricane wind scale, ranging from category one through five for winds speeds starting at 74 mph (64 knots) and the last category denoting winds greater than 157 mph (137 knots). Tornadoes use the Enhanced Fujita scale, ranking tornado intensity. The lowest damage category ranges from 65-85 mph (56-74 knots) and the highest category denotes wind speeds greater than 200 mph (174 knots).
Today the winds are still blowing powerfully at low 30 knot speeds, but we went out anyways. It was fairly miserable, but science cannot be stopped. And we cannot really afford to let some wind prevent us from utilizing this time to finish the field work. Two days ago I woke up early to start going through the samples to bag and box them up in the wooden rock boxes for travel back to Santa Barbara. After these two days of blowing snow, the samples are all buried. Hopefully we can find them all. Fortunately I set them out numerically in rows, so it shouldn’t be too difficult to figure out. The toilet tent has been reduced to violently flapping tethers of shredded tent material. The wind very effectively destroyed that tent with little effort. Hopefully the winds stop soon. The number of camp chores are growing and none will be fun with this wind. To top it off, on the return ride to camp, Demian’s and my bags fell off the sled. John found them back at the south side of the moraine arm we cross heading north away from Ascent Glacier.