An erratic few days

Katie Joy | 05 Jan 2020

A busy few days for us in the field. We covered a bit more ground with the metal detection panel array system on the main local ice field , but then suffered a few setbacks when the system powered up and down again in a run. Geoff and Wouter had a day of taking everything apart, assessing what was working and not working, and in progress we discovered that the blue sledge (we had nicknamed Sledge Evatt Junior*) that was carrying our control box and battery had a rather large whole in the bottom, which had been allowing snow to enter the base of the sledge dislodging some of the equipment. Needless to say Junior has been now been retired, and we need a name for the new blue sledge which has taken its place (number 3 doesn’t really have a ring to it).

An ice pond next to Halliday ridge: several of the local rocks had clearly sunk into the ice leaving interesting bubble trails during their descent. Alas no meteorites. [Credit: Katie Joy]
Looking along the ridge of Halliday Nunatak. [Credit: Katie Joy]

Whilst all the fixing up has been going on, Romain, Taff and I covered quite a lot of ground surface searching the northern most part of the ice field — finding 7 more meteorite stones throughout the day, including one (a stony type) that was almost completely buried within the ice, only about 10% sticking out of this surface. The clouds lifted and the afternoon was warm and glorious to work in.

Last night we had a good 20 knot wind sweep through the area clearing a lot of the snow off the blue ice surface. We all headed out as a group of five to visit the ice field closest to the Recovery Glacier — a trip of about 10 km from where we are camped. We travelled there linked up on skidoos — forming a caravan of skidoos and sledges trundling across the sastrugi snow heading north for about an hour. BAS fieldguide Julie Baum and I visited this icefield last year (it was the site of my epic skidoo breakdown), and it was good to revisit it. We searched the surface for a while, finding one more meteorite sample (adding to the three we found here last year).

Systematic search on ice. [Credit: Geoff Evatt]
Wouter and Taff near Halliday Nunatak. [Credit: Geoff Evatt]
Meteorite collection with tongs. [Credit: Geoff Evatt]
Geological search on Halliday Nunatak. [Credit: Geoff Evatt]

We also scaled the local nunatak — the only rocky outcrop in this area**, to collect some geological samples and to take in the view of the ice fields and how they extend northways abutting the Recovery Glacier itself (the boundary between the two features is impressive, with large ridges, crevasses and ice cliffs). We assume this is a first ascent — so will take this high with pride. The nunatak is formed of a weathered igneous rock (granodiorite), but has lots what we call ‘erratics’ (they are called erratics as they shouldn’t be there geologically speaking) all over the top that have been dropped from the bottom of a glacier which used to run over the rocky peak. Tomorrow we plan to return to the metal detection panel searching and see how sledge number 3 (we really do need a better name) holds up. May his bottom not be broken.

Group ascent of Halliday Nunatak. [Credit: Geoff Evatt]

* You might be wondering what/who is Sledge Evatt (i.e., the senior). Well this bold name was given to the blue sledge that was carrying the control equipment for the first sledge unit we set up. Alas, senior had to be retired a few days ago when he also developed a large hole on his underside, passing the responsibility onto junior…

** Recently we requested to name this site Halliday Nunatak after Dr Ian Halliday (1928-2018) who was a Canadian astronomer with expertise in meteor (asteroid and comet) delivery rates to the Earth. His research is related to our core science project of understanding Antarctic meteorite type, delivery rates and glacial transport processes.

The return of blue ice

Geoff Evatt | 03 Jan 2020

Good afternoon from Outer Recovery, where I’m lying in the tent I share  with Wouter and Taff, having enjoyed a lunch of biscuits brown, soup and sardines.  Yep, austerity is in full swing! Even the cloud is down outside,  but it’s not too cold today (probably –10ºC or so).

Geoff waits out a low contrast day at camp.

We have been continuing with our search, and have covered almost 0.7 km2 with our system hanging on by its shoelaces (in fact, gaffer tape and cable ties). For clarity, that is the area our metal detector has sensed, whereas the area we have travelled over visually searching for surface meteorites is several times that. Our second system had to be decommissioned yesterday, as the huge batteries (car battery-sized) have now given up the ghost, such is the thumping the blue ice surface has been giving to everything, day in, day out. I’m hoping we will reach 1 km2 before it is no more…

Taff drives a skidoo, towing the metal detection array. [Credit: Geoff Evatt]

Simultaneous to this,  we had a bit of wind return the other evening, just long enough to remove some of the snow that recently fell (plus maybe a small bit of sublimation caused by the sun). This meant that some blue ice became visible again, and allowed for 6 meteorites to be collected yesterday and one more this morning. I think the total from this ice field is about 54, which is pretty good and spot-on for the number we had predicted given the area searched — at least the statistics are more or less behaving themselves! Weather tomorrow is forecast to be overcast again, with good weather after that. If that holds I think we’ll head to a small ice field adjacent and north of camp. There we will look for any surface meteorites,  climb the nunatak (the mountain top just poking through the ice) which we officially named Halliday, and generally get a change of scene.  And given it’s the only bit of non-meteorite rock I will have seen in over a month, it will hopefully be a welcome jaunt.

Let it not snow…

Katie Joy | 03 Jan 2020
A layer of snow covers the blue ice field. Helpful for subsurface searching; definitely a hindrance for surface meteorite hunting. [Credit: Katie Joy]

What a difference a bit of weather makes. This whole area was stunning blue ice a couple of days ago. Two days of gentle sustained snowing means that the whole icefield is now buried under 5 cm of snow. This is useful for the metal detector dragging activities (see Geoff’s last post) as it means that we can very easily see where we have driven (in the image above the panel tracks can clearly be seen in the lower half of the image, compared with the unsearched area in the upper part of the photo). On the other hand, these conditions are absolute killers for the surface meteorite searching activities as all the meteorites are now very disappointingly disguised by the snow cover. We need a night or two of 20 knot winds to come in and blow hard to shift all the snow. However, the weather is forecast to remain the same (~ –10ºC, 5 knot easterly wind, patchy sun and clouds) for the next couple of days.

In the meantime the subsurface meteorite hunting activities continue using the metal detector panels – we have now managed to search about 0.6 square km of the ice surface, with Wouter being an absolute legend fixing bits of the system that fail with all the bumping around on the hard ice surface.

Ploughing through the snow… Romain dragging the metal detection setup. The rough surface in the foreground is where the panels have been pulled through the snow creating obvious drag marks. [Credit: Katie Joy]

The benefits of snow…

Geoff Evatt | 02 Jan 2020

The cloud has lifted and progress has been made. Yep, in a true A-team style our patched-up systems seem to be working (as in, two systems with a combined searching width of 4 meters). And we searched for almost 8 hours. No subsurface meteorites,  yet (statistically,  we are only expecting a handful of iron meteorites over the entire 12km2 ice field). But what is certain is that if we’re not searching then we can’t be finding them.

As for conditions, well, it’s now all snow covered,  meaning no blue ice is visible anywhere. Whilst this makes the subsurface searching easy to progress (because you can see where you’ve been and removes vibrations in the system), it makes seeing any surface meteorite impossible. Personally I’m hoping the snow cover lasts for the rest of the trip!

The next couple of days are forecast to be similar nice weather with low winds. So let’s see if our relative fortune holds for tomorrow.

Bon réveillon a tous !

Romain Tartese | 31 Dec 2019

Une fois n’est pas coutume, voici un blog en français pour les quelques 3 ou 4 francophones qui suivent notre périple Antarctique ! Ça fait maintenant une dizaine de jours que nous sommes réunis tous ensemble sur notre zone de recherche de météorites, par 81° de latitude sud. En général la météo a été plutôt clémente jusqu’à présent, avec de belles journées ensoleillées accompagnées d’une légère brise venant de l’Est, et des températures généralement entre –10°C et –15°C. Jusqu’à maintenant nous n’avons été ‘coincés’ au camp que deux journées, et on croise les doigts pour que cela dure.

Nous avons donc pu arpenter en motoneige une bonne partie du glacier à côté duquel nous sommes basés, et avons collectés une cinquantaine de météorites à la surface (à ajouter aux 15 météorites collectées sur ce glacier l’année dernière par Katie et Julie). Il a pas mal neigé ces derniers jours et malheureusement la glace est maintenant couverte par 5-10 cm de neige, ce qui rend la recherche de météorites a la surface impossible pour le moment. On espère donc de bonnes bourrasques de vent pour dégager la neige du glacier, et continuer notre collecte.

Une belle pièce ! [Crédit : Katie. Joy]

Dans le même temps Wouter et Geoff ont fait face à pas mal de problèmes avec les détecteurs de métaux que nous trainons derrière nous sur la glace — les vibrations ne font pas bon ménage avec les boitiers électroniques. Mais à chaque problème il y a une solution, et au jour d’aujourd’hui nous avons 2 systèmes qui fonctionnent. Il nous reste deux grosses semaines pour couvrir le plus de surface de possible avec les détecteurs de métaux afin d’essayer de trouver une météorite ferreuse enfouie a quelques dizaines de centimètres sous la surface (nos estimations prédisent quelques météorites enfouies pour une surface d’environ 10 kilomètres carrés !).

Si on dégote une boite de thon on va se faire une ‘gueuleton’ ce soir pour le réveillon, à base de pates, thon et sauce tomate ! De votre côté, n’abusez pas trop sur le foie gras ! Nous vous souhaitons un bon réveillon a tous, et un très bon début d’année 2020 !

New year, new start?

Geoff Evatt | 31 Dec 2019

Hello from Outer Recovery as we approach the end of the decade. Low cloud and poor contrast abounds today, so we’re confined to the camp, giving us the chance to tinker with the system and get some rest (the ambiance outside is currently Nordic,  and not unwelcome). The last few days has seen clear positive progress.  As in, we seem to have salvaged a working core of the detector system. And we have been out doing systematic searches with it, covering a reasonable area, all things considered. Issues seem to pop up every 3 hours or so, but in those hours the system is working amazingly well. In fact, after some re-engineering of a sledge yesterday, we finally have two operating systems (one as 5 panels although only three of these are working, and the other is now a single panel system), meaning we can search a width of 4 metres as we travel along. Let’s hope those 3 hours of search time start creeping upwards…. this whole project is a numbers game: the larger area of the ice field we can search, the more likely we are of finding a lost iron meteorite.

Katie and Wouter soldering. [Credit: Geoff Evatt]
Wouter using parts of one metal detector to fix other. [Credit: Geoff Evatt]

Other than that, our surface meteorite count for this season is now 42, which is great, especially given the relatively small area we are searching (this blue ice field is just under 12 km2, but maybe a fifth is hidden by sastrugi, making it impossible to search). After strong winds the other day, some of the snow cover altered, and Katie and I found a nice chondritic meteorite where a sastrugi existed the day before.

Sledge Evatt getting some TLC. [Credit: Geoff Evatt]

Food-wise we seem to be doing OK.  It appears the vast number of calories we had at Rothera cause our metabolisms to increase, meaning that when we first hit the field with far less food, we rapidly got thin. But now our bodies seem to have taken the hint, and the weight loss seems to have slowed. Or maybe we’re just eating more biscuits brown and porridge. Does this mean we’ll balloon as soon as we hit civilisation again? Either way I’m desperate for a run or cycle, but conscious that the general wear and tear on the body may mean it’ll take a while to be back to normal. Yet I can now drag metal detector panels for Britain. Maybe we now have the world record for doing so down here?!

Romain driving one of the detector arrays. [Credit: Geoff Evatt]

Getting surface meteorites in the bag

Katie Joy | 27 Dec 2019

Whilst the panel testing is continuing (see Geoff’s last blog post) we have also been making steady progress with searching the ice surface for meteorites that have emerged from the blue ice. As of today the count is at 35 stones from Outer Recovery — one off the total for the whole of the last recon field season.

Katie and a large meteorite “find”. [Credit: Romain Tartese]

Every rock we locate at this particular ice field is a meteorite — there are no terrestrial rocks at all, so it makes identification very easy. What is tricky is actually spotting them in the first place — often the meteorites are hiding at the bottom of suncups (small depressions made as the ice is ablated by the wind and sublimated on warmer days), and for those less than a couple of cm in size you have to be lucky to see them as you drive past on your skidoo and be looking in the right direction (for this reason we swivel our head continually as we drive like watching an end-to-end tennis match). Samples bigger than ~3 cm are easier to spot, but again can sometimes be nestled down between snow patches or in suncups. Whether you are driving into the sun, and the angle of the shadows cast at different times of the day comes into play, so although we are systematically trekking back and forth across the ice surface, not every search session results in a meteorite find: between 2 and 7 meteorites seems to be the rate of daily collection at the moment.

A small but perfectly formed flight orientated stone. [Credit: Katie Joy]

The meteorites themselves vary from a small bean-sized one we found yesterday (a lovely perfectly fusion crusted stone, suggesting that this tiny meteorite is a complete piece), to another complete stone which preserves a fusion crust that is flight shaped (i.e. we can tell which in orientation the meteorite was delivered as it travelled down through Earth’s atmosphere — these type of samples are very aesthetically pleasing, and are really cool to find), to some larger blocky stones (around the 8-20 cm size range) that look like they are pieces of a large meteorite that broke up either in space, or through erosion as it was transported through the ice [NB I am guessing that they are from the same parent meteorite at this stage based only on the colour and texture of their exterior surface, and the very similar colour and texture of their interior — this will all need to be confirmed when we do the formal classification back in the lab]. Several of the samples we found this year are like some of those we found last year, suggesting that again there might be some relationships between the samples we have collected, and others look completely different which is exciting as it means we have good diversity across the sample set collected.

So, all in all, we are progressing steadily, and hopefully will continue to get more meteorites bagged up. Today the weather has turned snowy so will have to see how this effects our search plans over the next few days.

Hope that everyone had a Happy Christmas — we had a tasty meal last night together complete with an amazing Christmas cake provided by chef Olly at Rothera (many thanks — you are a star!), and had a team drive out after testing the panel array to visit a cool ice rise (which is a bit of ice that has been squeezed up to look like a pointy mountain tip) next to the search area.

Geoff driving the detector panel arrays on the ice surface. [Credit: Katie Joy]
The team visiting a nearby ice rise on Christmas Day. [Credit: Katie Joy]

PS Many congratulations to my Aunty Angie and Tommy for getting engaged. Sorry I cant be there to celebrate with you all, but raising a cup of tea to you from the field.

PPS Thanks Isotope Group crew for sending down the birthday card. Very sweet of you all to get so organised in advance. 🙂 Much appreciated. Hope that you are all well and looking forward to the BPSC.

PPPS Dutch, we found some pina-colada flavoured energy bars in the manfood box. Definitely not as exciting as the real thing.

The weather outside is frightful…

Geoff Evatt | 26 Dec 2019

Hello from Outer Recovery,  where we are spending Boxing Day cooped up in our tents as the weather outside is not so great today…. meaning I have the chance to give a status update.

Working on the detector system. [Credit: Katie Joy]

All of a mixed bag really. The positive news is that we have begun searching for the lost meteorites! And when searching, the system is performing rather well (we can see our trial targets down to almost 20cm in real time, with minimal false positives). The bad news is the combination of vibrations, cold, and extended periods of operation are battering the system, meaning we are spending most of the time patching it up.

Views from a Christmas Day walk. [Credit: Geoff Evatt]

To give an example, yesterday we found the main power cable from the solar panels to the batteries had snapped clean through, in two places.  This cable was Antarctic rated and successfully used in other projects. But the high pitch vibrations being put through the system by the scalloped ice surface, means that even the tiniest of weaknesses are soon exploited. And this particular one has consequences: as it snapped it caused the solar panel regulator to be permanently damaged, meaning we can no longer use the solar panels to charge the batteries, so we have to rely on a generator, which in turn means it takes much longer to charge the system…. and that’s after several hours of trying to identify and fix the problem…. This example shows what we ‘re up against. And with the whole search being a numbers game (for this particular ice field, we have predicted 3-4 subsurface iron meteorites) then, we have to search a large area to stand even a slight chance of finding one. But we are progressing, albeit haltingly.

Meteorites in hand! [Credit: Geoff Evatt]

In other news the surface search is moving forwards well, with over 30 meteorites collected so far. From their appearance we seem to have collected a good diversity of samples, which is welcome news. We had predicted around a hundred meteorites on the surface for this icefield (give or take), and as that includes the 15 found by Katie here last year, then we are moving steadily towards that estimate. And that’s not taking into account that the blue ice area has over a 20% snow covering, meaning over a fifth of the predicted meteorites are out of view.

We also managed to ascend the ridge overlooking our camp yesterday, to find a stunning view down over the blue ice plains below, with (surprise!) yet more Antarctic plateau behind. It was a great way to round off Christmas Day, before heading back to a lovely smorgasbord of food and cake.

In the meantime we’re sitting out the bad weather, and about to commence with yet more repairs on the system….

Sunny skies and finding meteorites

Katie Joy | 22 Dec 2019

The team is all together now at our Outer Recovery fieldsite! The last few days have seen a lot of activity. On the 19th I flew from Halley with pilot Mark to drop off the science kit at Outer Recovery with Wouter and Geoff — this included the final set of panels and our meteorite extraction equipment. Then a series of short 30 minute flights took us to a refuelling depot, over to Romain and Taff to collect a skidoo and a Nansen sledge, back to Geoff and Wouter to drop these off, back to refuel the plane, then back to Romain and Taff to pick them and the final skidoo up, and finally drop everyone off at Outer Recovery site.

The team looks onto a recent find. [Credit: Katie Joy]

It was a pretty long day with a lot of flying, with a lot of skidoo loading and unloading onto the planes (this whole exercise is a right pain in the butt – the skidoos just (just) about fit through a Twin Otter door and it takes four people to rotate, bump, pull and push them in and out of the plane). Finally, we were all together as a team, and the next day we waved goodbye to fieldguide Rob who returned with pilot Mark to Halley, before moving camp 2 km down the road (or rather sastrugi-covered surfaces) to set up on the edge of the blue icefield where we will be working. It has been sunny, cold but very windy (we reckon about –22°C with windchill) at the field site. Yesterday, the summer solstice, brought a day where we explored the ice surface, finding 7 more surface meteorites (a nice mix of shapes and sizes, with several looking different to each other), and did some more in-field testing of the panel arrays – we have been burying small iron dummy meteorites to tune the system to working on ice (rather than the rocky cargo yard at Rothera, or the soil field at Whaley Bridge).  The wind has dropped, the temperature is up and today the plan is to do another testing round out on our practice search area to get the system finalised. Hopefully we will be in a position to begin buried meteorite searching soon, and in the meantime will do some more surface searching. 

Geoff with a recent meteorite find. [Credit: Romain Tartese]