A quick update to say that we arrived safely back at Rothera Research Station around 9 pm last night. Vicky put in an amazing effort to get us back from Halley on the Twin Otter all in one day with bad weather swirling around. Goodbye to Halley and the fab team of people who are working really hard there to wrap up the end of their season of work. Thanks so much to all for making our field season a success and for your hospitality looking after us so well.
The views on route as we winged our way west were amazing out of the window (when I wasn’t snoozing) and we got a great view of the mountains close to Fossil Bluff through the mist and also saw a glory in the mist layer (see photo and caption for more). On flights like this, you realise how big Antarctica is and how flat and white and expansive most of the landscape is — just miles and miles of sastrugi-covered snow surfaces, with the occasional crevasse or rocky nunatak to break the horizon.
Rothera has changed somewhat since we were last here, with the new wharf works ongoing, but there are a few seals swimming around in the bay. Today has been a day of sorting out shipping and items to get back home before I am due to fly back tomorrow on the Dash 7 back to Punta and then onto the UK over the weekend.
Spending time at Rothera before we transfer out to the field has been great and given me a chance to see some of the local wildlife, see some spectacular scenery, and meet the great people to work hard to keep the station and field operations on the go. The next few blogs will hopefully give you some insights to what life is life at the research station.
What is there to see around the station?
When there are no planes landing you can walk around the perimeter of the gravel runway which gives some good views of the station and also of the surrounding bay. It takes about 20–30 mins at a slow (photo-taking pace) to walk around the edge. A couple of days ago I was lucky enough to see a group of three Adele penguins waiting patiently at the runway crossing point — and yes I was as excited as you can imagine. They are super cute, flapping their wings and all. Like all the animals and birds in Antarctica you have to stay a respectful distance away so not to disturb them, and these three guys moved on to an open water patch soon afterwards.
You can also walk around the Point behind the station. It takes about an hour and a half to take a slow meander around a marked path, avoiding a specially protected area on a hill top behind the station (this area is kept people free to track the effects of people on the occupied part of the Rothera Point). You have to check out of the station, so that people know you are heading out and about, but once on the walk you can take your time and enjoy icebergs bobbing around and breaking up – all the time the smaller ones are on the move by the tide. The colours, especially on a slightly overcast day, are amazing different tones of blue through clear glassy and snowy white. There are some small patches of moss that grow between the dark granodiorite fractured rock. There is currently a large berg with an arch in it bobbing around in the bay. On the way you see various science experiments (a solar observatory) and radar and weather observations stations, along with the communication satellites.
What wildlife can you see?
So far on my stroll to look at the icebergs around Rothera Point I have seen more elephant seals (they are everywhere…), some crab eating seals on the land and also a collection of about 30 of them fishing in the sea together in a big group, and a couple more Adele penguins hanging out on the sea-ice edge. Bird life include skuas (large gull-like birds), kelp gulls (black backed), arctic terns fishing (beautiful and amazing — they can travel 19000 km a year to migrate between polar region food grounds), snow petrels, and the little dark coloured Wilson’s Storm-Petrel. The sea here apparently has increasing levels of plankton which means that soon there will be krill moving into feed, which are often followed by orcas and other whales.
What do people do otherwise for fun?
For those living here (often for up to 18 months at a time) the appeal of living on the station needs to include recreation activities to give people some downtime to relax after working days. There are a couple of TV rooms and movie nights run, there is a well stocked library and quiet reading space, games (lots of board games), people run a knitting club, and there are yoga classes advertised on the mess room board. There is a bar with a pool table and table football, and once a week football game. The people that live and work on station can also do other recreation activities like cross country skiing and downslope skiing on a ramp close to the base – given how clumsy I am and a terrible skier (no matter how good the coaching is I prefer to adopt the snow plough in most ski situations…) — I will be giving that a miss so that I don’t take a tumble and damage myself before getting a chance to do our fieldwork!
I am currently in the town of Punta Arenas at the southern tip of Chile. This small city is the exit point for flights over to Antarctica (and ship departures to the polar oceans). To get here I flew from London Heathrow, to Sau Paulo in Brazil, over the Andes to Santiago and down to Punta — a journey of about 36 hours so am pretty tired. Today we had a look around the town, which is pretty bustling – full of tourists setting off for adventures in Patagonia, and have had a briefing about our departure plans.
Two of the US Antarctic Program icebreaker ships — the Palmer and the Gould are currently in port here in Punta Arenas, ready to head south to the Palmer research station and help support science operations for the Thwaites Glacier research project, ongoing this season in western Antarctica – a complex (there are 9 different science projects) international collaboration between the US and UK polar research programmes.
Our field equipment has arrived safely in Antarctica on the RSS James Clark Ross ship, which just moored on base, and is now awaiting my arrival to get unpacked and ready to send onto the field site. We haven’t seen it since we packed it up in Manchester in August, so it will be good to be reunited with the kit again and get ready to start the field season.
If the weather holds hopefully I will fly out with several other BAS staff and contractors working on the new dock to Rothera research station on the Antarctic peninsula on BAS’s Dash 7 plane . The journey over to the continent should only be about 5 hours, but there is always a chance that the flight might get scuppered and bounced back to Punta, or we might not be able to depart at all in the weather around the peninsula is not good. Hopefully my next post should be from Rothera unless the weather is too bad to fly… keeping my fingers crossed.
One of the important parts of collecting meteorites is detailed record collection which allows for efficient curation and identification when the samples are returned from Antarctica. In addition to where a sample was found, we need to know what it is (and be sure that it is a meteorite after all!). As mentioned in a previous post, in addition to her familiarity with collecting meteorites in the field, one of the ways that Katie might be supplementing her preliminary in-field examination of the samples is by using a CEREGE-built portable combined magnetic susceptibility – conductivity field probe. Magnetic susceptibility is a measurement of the degree to which a material will be magnetised (induced magnetisation) when a given magnetic field is applied. Conductivity is an electrical property which allows a material to conduct electricity.
Following an initial blank air test, the sample is placed close to the probe, reacting with the weak magnetic field generated by the probe. The extent of the reaction is correlated to magnetic susceptibility, and also affected by electrical conductivity. Both properties are then quantified using correction based on sample volume (Gattacceca et al., 2004).
The predominant component of meteorites which can be magnetised is the meteoritic iron (i.e., iron as Fe rather than oxidised phase like FeO or Fe2O3). The meteoritic native iron content of meteorites varies quite reliably with the classification of its type (stony, stony-iron, iron), which depends on its composition, thus linking to its original process of formation. Meteoritic iron is also electrically conductive, whilst terrestrial rocks usually are not. As such, the AnMetMet is able to tell the difference between metal-bearing samples and iron oxide (e.g. Magnetite) bearing samples, a separation that cannot be achieved using a magnet which is sensitive to magnetic susceptibility alone.
Because of this, performing a magnetic susceptibility-conductivity test gives a good estimate of its classification – and can be used to confirm that the rock is indeed a meteorite rather than a terrestrial magnetic rock or mineral. A sample must be above a certain volume for accurate readings, but if they are relatively homogeneous, even large samples (larger than the probe) can be measured.
The magnetic field generated by the probe is weak, similar in intensity to the natural Earth field, so that the natural remanent magnetisation (NRM) of the sample is not disturbed. This is crucial because the NRM of meteorites is of great scientific value as it bears the record of ancient magnetic fields that may have been present in the early solar system, generated within the solar nebula or by dynamo phenomena within planetesimals. For that reason, the use of magnets to test the meteoritic nature of a rock should be avoided at all costs because it both inefficient (non quantitative) and destructive for the magnetic memory of the rock.
To ensure that we understand the numerical output of the probe in the field, we are testing it on some test meteorites we already have here in Manchester (these are the same samples we have been testing our metal detector panels on). Amongst the test subjects are pieces from NWA-869 – an ordinary L chondrite, Gao Guenie – an ordinary H chondrite, Campo del Cielo – an IAB iron meteorite and a few fragments from the ordinary LL chondrite Chelyabinsk fall (which some might remember from the dash-cam videos in 2013).
The aim is to piece together a reliable framework of readings so that we can be sure of how potential finds fit into the meteorite classification scheme. In addition to this, we will be testing the probe at low temperatures to see whether the readings will vary from room-temperature measurements when they are faced with the significant chilliness of Antarctic weather.
If all goes according to plan, we’ll have a useful database to complement Katie’s in-field measurements, which will be a good aid for future sample curation planning and analysis. Big thanks to Jérôme Gattacceca for making sure this explanation is accurate!