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.

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