Antarctica part 5 - the Churchill range

On November 17^th, in our camp at the bottom of the Holyoake “ridge”, I woke at 5:00am to start calling in “hourly” weather observations to McMurdo. An “hourly” is a quick, standardized weather observation that includes wind speed and direction, temperature, dew point, sky coverage, and ground definition. If the sky is clear it’s quite easy: alarm goes off at ungodly hour, I crawl from sleeping back to door of Scott Tent with Kestrel pocket weather meter in hand, I do downward-facing-dog to exit the door; I stand up outside, take the weather readings, and crawl back in – all in less than 5 minutes. I call Mac-ops on the HF radio, and report my observations; I set my alarm for a 50 minute nap, I go back to sleep, only to repeat again 6 more times on the hour until the Otter is inbound. So this time, 5:00am, I find it a little depressing because the wind is blowing at 40 kts, and it’s actually hard to stand up outside, let alone conceive of how a small airplane could negotiate such a stiff, turbulent, katabatic wind  to arrive at our camp. It seems as if half the eastern ice sheet is now airborne, bouncing along, grain by grain, drifting in between our tents.

Hour by hour I call in my “hourlies”. Each time I wake I think how fruitless it seems to try to get an airplane into such a windy, mountainous spot. I never give the sturdy Twin Otter enough respect.

We pack up our camp starting at 7:00am… We are soon told on the radio that the Otter is inbound, and ETA of less than an hour.  It takes four of us to wrestle a Scott Tent down out of the wind.

At the appointed time, someone sees it… “There’s the OTTER!” - their voice barely audible over the wind.

The airplane buzzes around for a while. We are convinced the pilot is about to pull the plug and fly home. The plane disappears. I’m about to call Mcmurdo to hear of our fate. Then someone spots it again – this time taxiing over bumpy, sastrugi-covered glacier a mile away. 

Against all odds (and against a robust headwind) the Otter arrives, and we stuff it with our cargo. It takes two flights to move us to the Churchill Range, where we land in an almost wind-free environment. The difference is staggering, and now we can hear ourselves think! The Otter returns to Mcmurdo with Paul Myrow and 600 pounds of lower Cambrian trilobites, isotopic samples, and bulk samples of various limestones and siltstones on board. But we are left with a hefty resupply of food… More frozen steaks, salmon, rice, cereal, and two bottles of Tabasco! - well stocked for another several weeks of posh Antarctic living - and then some...

The crew erects Scott Tents, mountain tents, and our fairly flimsy toilet tent in record time - taking advantage of the calm conditions. We settle in to our first night at the new site, planning our attack for the next week of fieldwork.

The goal at this new site is the same: Collect limestones containing small shelly fossil material from the lower Cambrian in order to make more clear the sequence of evolutionary events leading to the development of the more familiar taxa that emerged during the later lower Cambrian.

We spend the better part of a week scrambling up two different ridges – each one within 3 miles of camp. Compared with the last camp, where we were pulling trilobite heads out of siltstones by the fist-full, this rock seems devoid of any larger well-preserved fossils. Despite this, the team bulk-samples different litholigies on both ridges, Lars Stemmerik does a section of painstakingly detailed sampling for isotope geochronology, and Christian Skovsted scrambles where none have dared to scramble before – in the hopes of recovering some reclusive trilobite samples. When the work is finished after a few days, a blessed spell of high pressure just happens to depart the McMurdo area, making way for the Central Trans-Antarctics, Ross Ice Shelf, and McMurdo region to be covered by a warm, moist,  but calm low pressure system. We spend one extra week (not altogether uncommon in Antarctica) sitting around, eating extra food, reading books (I finished Worst Journey in the World by Apsley Cherry-Gerrard), working on the best lowe-visibility glacial landing strip in the world, and walking up any piece of exposed rock within three miles of camp.

Finally on Monday, November 28^th, perfect weather allows a KBA Twin Otter to pluck us out of our camp and back to Mcmurdo, where showers, beer, food, and departure paperwork await.

Another Antarctic field season in the bag... I've added some photos of the Christchurch Range camp below.

Airborne view of Ross-age folding between the Holyoake and Churchill Ranges

Crevasses on the Starshot Glacier

The team at the new Churchill Range camp.

Dr Lars Holmer staying hydrated in our kitchen "Scott" tent.

We climbed two different ridges from our camp in the Holyoake range. This is the view looking east from the top of one of them. The two peaks in the distance are called the "Cupcake Peaks". The glacier flowing east is called the "Entrient Glacier".

Alternating intertidal (light-colored) and offshore marine (darker) limestones near Mt Moa.

It's almost as cold as it looks... An afternoon squall dusted our ridge with fresh snow, and motivated us to wear as much clothing as possible... In the image above, Lars Holmer takes one last search for fossils before calling it a day.

Lars Stemmerik and Christian Skovsted searching for fossils near our camp in the Churchill Range.

View of our camp, looking south, towards Mount Moa.

There was a distinct pleasure in being able to wash and dry dishes while sitting outside the Scott Tent at night.

Lars, with the Entrient Glacier and Cupcake Peaks in the background. What a successful season of geologic sampling in Antarctica ought to look like...

A real-life unstaged high five when the Otter arrived to pick us up (we had been stuck there for an extra week).

McMurdo-bound in the back of a Twin Otter, and thoughts turn to showering. On our way home, we flew over the Byrd Glacier, the world's biggest valley glacier.

Antarctica part 4 - the Holyoake range

Almost nothing ever happens ahead of schedule in the Antarctic. Typically, flights are delayed by days, sometimes weeks. On my first trip to Antarctica, I spent 9 days waiting in Christchurch to come down. On my second trip to Antarctica, my return trip to Christchurch was weather-delayed by 8 days.

Anyway, I guess its the law of averages - we arrived in McMurdo on October 27th - A friday - and managed to leave McMurdo a week later - on November 5th. That's just enough time to finish training, pack food, prep cargo, print maps, etc... without being too slapdash.

All of our cargo and our motley group of six passengers were stuffed into two twin otters. The total weight of people plus gear was 4200 Lbs. That's not really a lot when you think about it. 6 big fellas with heaps of down clothing on, plus personal sleep kits and backpacks, etc... weighs about 300 Lbs each. Our skidoo weighs 400Lbs, and add in another 150 Lbs for fuel... That leaves 1900 Lbs remaining for tents, stoves, glacier gear, shovels and saws, toilet buckets, wooden rock boxes, and a helluva lot of food. We took up every allotted pound of weight. No one ever goes into the field in Antarctica without less than about 2 weeks of emergency food (in case bad weather delays your retrieval), and about one book per week. We stuck to that formula, but to the bare minimum. For books, I took an Amazon kindle - the first time I've ever done so in a cold mountain environment. It worked flawlessly.

We flew 2 hours to the Holyoake Range - a small sub-range of the Churchill Range - a middle-sized range tucked into the Trans Antarctic mountains between the mighty Nimrod Glacier and the even mightier Byrd Glacier. Our camp was placed on a trifling tributary called the Errant Glacier. The Errant would easily dwarf the Kahiltna or Aletsch glaciers.

Now many people who read this might notice that I've spelled our location H-O-L-Y-O-A-K-E. Some might be more familiar with the Holyoke Range of Massachusetts. However, our little mountain range was named for the Rt. Hon. K.J. Holyoake - who was once upon a time the Prime Minister of New Zealand, and who looked very favorably upon IGY-era Antarctic exploration. That's all I know about him.

November 5th is early to be in the Trans Antarctic Mtns. We feared cold. But when we landed on the butter-smooth Errant, we found calm, mild conditions.  During our 1.5 hour wait for the second otter, Travis and Lyndsey - the KBA otter crew -  basked in sunshine, drank cocoa, and watched us erect our Scott tents. - We were blessed with 24 more hours of nice, calm weather. By mid-day of day-2, it was blowing a gale. We had 20-40 knot winds for every day we were there - except for two. Temperatures ranged from a balmy -7°C down to a chilly -19°C. But at least it was always sunny.

Above our camp a sinuous ridge of steeply dipping Cambrian carbonate rocks extended up to a plateau to our (grid) east - towards the ice shelf. The ridge was flanked by glaciers. One glacier was directly above us, and it was mostly crevasse-free. This became our daily commute to "the Holyoake ridge". Paul Myrow was our veteran of this site. Together with John Goodge, Paul had noted the basic stratigraphy of this site a little over 10 years ago, working on previous studies by A.J. Rowell in 1988.  At the bottom of the sequence lie beds of Shackleton limestone - tortured, tectonized black offshore deposits with nothing of interest to the naked eye until one moves farther upsection.  Dip was near-vertical and perpendicular to our ridge. Traveling up-ridge is the same as traveling up section - the rocks keep getting younger. The limestones are now interrupted by the occasional shallow reef sequence, containing abundant archaeocyathids (primitive, reef-building sponges). Above the uppermost reef, siltstones interbed with thin nodular limestones, grading into pure, trilobite-rich siltstones and mudstones for about 75 more meters before slamming into the base of the Douglas Conglomerate - an abrupt and spectacular contact indicating rapid uplift and drowning of shallow marine facies: i.e. - the onset of the violent, Gondwana-wrecking Ross Orogeny of the middle Cambrian.

Once our team spotted the archaeocyathids, they knew they were on target. These old critters only existed for a relatively brief window in geologic time. They first appeared around 530 million years ago, but they were all but gone by 515 m.a. One problem with our rock sequence was that it was extremely sliced up by more recent faulting and shearing - to the point where it repeated the sequence over and over again along some parts of the ridge - like a geologic Bill Murray's Groundhog Day.

We found trilobites below and above and together with the archaeocyathids. We collected hundreds of pounds of exquisite trilobites specimens, now in wooden boxes on the way to some specialists in California for more precise taxonomic I.D. The team bulk-sampled the rock at every major lithological change, hoping to collect phosphatic fossils from early brachiopod ancestors - tommotiids. For more about the tommotiids, and the controversy over their origin (and the origin of brachiopods), you can read a short description about them on wikipedia. On the references cited at bottom, note that most of the authors were present on this Antarctic expedition.

When it comes to these small shelly fossils, only time will tell. The bulk samples are being sent to Sydney, AUS, where Glenn Brock will soak them in ascetic acid (vinegar) until the limestone matrix dissolves, and the phosphatic shelly fossils fall to the bottom of the bucket. These microscopic fossils will be analysed with Scanning Electron Microscope. The goal is to fill in the gaps and sort out exactly how brachiopods evolved into their currently accepted phylum.

Overall we spent 10 days at this site, piling into the skidoo and siglund sled every morning, traveling 3 miles over bumpy sastrugi to our parking spot, and walking up a really steep hill of scree to the land of many trilobites. On November 17, Another Twin Otter arrived in the midst of 40kt gusts and blowing snow, and transported us - taking two trips - to a new site in the Northern Churchill Range. Stay tuned - that blog post is coming up next.

Airplane camping at the Holyoake Range.  

Rare: sighting two otters in one place in the middle of nowhere, AntarcticaOur daily commute took us 2.5 miles to the base of this ridge. Here, Paul Myrow begins fossil hunting on day 1. Lars and Paul looking at the first Archaeocyathid fossil.

We couldn't have done better picking a scenic place to work. Typical good weather working conditions... Paul and Lars are walking across a 30m thick reef layer at the upper end of the lower cambrian. Typical cold and windy working condtions - the Big Red's stayed on all day. Thh meter stick is for Lars Stemmeriks isotope sample collection. Dr Glenn Brock and a rare, complete trilobite.Camp Life: We chose to eat outside during rare lulls in katabatic wind. On a melt pool near camp.... This will be slush in late December. Lars, Paul, and more 50cm isotope sampling on a windy day.

Retiring to the skidoo at the end of another windy work day.

The site of much sample collection