Photogrammetry and non-destructive determination of properties of Antarctic meteorites

Tom Harvey writes:

Throughout ejection from their parent body, transportation through space and subsequent arrival on Earth, meteorites undergo extreme pressures and temperatures. Some meteorites, despite having survived entry to Earth, can be extremely fragile. Some of the analytical techniques that provide a wealth of information about meteorite geochemistry and physical properties can be damaging to a meteorite sample, either exposing it to some forms of contamination, or destroying it entirely. Given the opportunity to analyse relatively pristine samples from Antarctica, we opted to develop a procedure for understanding some of the fundamental properties of the returned meteorites that was entirely non-destructive.

Density (the mass per unit volume of a material) is a useful property to understand because it can allow us to make inferences about parent body composition, in addition to being an important metric in understanding thermal evolution models, as well as the survivability of materials in impacts, and during atmospheric entry to Earth. Non-destructive, high-precision measurement of the mass of a meteorite is straightforward to undertake using lab scales (i.e., weighing balances).

However, the determination of sample volume is not so straightforward. Traditional “Archimedean” methods for the determination of volume involve measurement of the displacement of a well-characterised medium (for example water, ceramic beads or inert gases) when the sample is emplaced into (see this previous study Consolmagno et al. 2008). Depending on the medium that the meteorite might come into contact with, it is possible that the sample might be chemically altered or mechanically damaged. Volume determination has also been performed by laser scanning of meteorite samples, to produce a three-dimensional (3-D) computer model of the sample surface topography (for example, see McCausland et al. 2011).  A potential barrier to performing this sort of study is the requirement for expensive and highly specialised laser and camera technology.

An alternative to these methods that we have chosen to develop is the production of 3-D computer models of the samples returned by the Lost Meteorites of Antarctica project. This method involves the use of a suite of photographs of an object to computationally generate a three-dimensional colour model of that object. The method is non-contaminating, scalable, and the only necessary hardware was a DSLR camera, some small portable lights, and a computer with the appropriate software installed.  Furthermore, the production of an accurate computer model of the samples’ surface topography and colour makes an excellent curatorial record which can be used in lab decision making, and to understand the orientation relationship between sub-splits in the future.

Tom Harvey in the curation lab imaging one of the meteorite samples. Photo: KJoy

First, the meteorites were placed into a controlled light environment. This meant that we could control the amount of reflection and shadow on the sample surface, which is important for producing a good model. By using the appropriate sterile tools and portable lights, this method did not expose the samples to any alteration or contamination. Photographs were taken using a high-resolution camera at 5º rotational intervals around the sample (and in multiple orientations to capture) to ensure that we had captured all the details of the sample surface.

These photographs were then loaded into Agisoft Metashape, a professional software for photogrammetry applications, which were used to produce the models. This process is broken into several key steps which involve a pixel matching algorithm, and alignment of the various orientations of the sample to generate a shape file for the sample, followed by the production of a mosaic derived from the sample photographs to map over the shape file to bring it to life in colour.

In order to determine the volume of these models, the shape files were imported into a computer-aided design (CAD) software, 3DS Max, and scaled according to known external sample dimensions, measured in the lab with a Vernier calliper. In order to understand how well this method determined the true volume of the sample, we produced models of wooden cuboid blocks of known size and found that the computed volumes of these blocks were within 2% of their true, measured volume.

Final model of Antarctic Meteorite OUT 18010, images of which are shown in the above slideshow. Video: Tom Harvey

Using the data from this method, we will be able to compare our computed volumes with measurements derived from other methods such as computed tomography scans of the sample. The photogrammetry derived volume measurements and the sample masses measured in the lab allowed us to compute a density value for each meteorite in the study. Once all of the meteorites are formally classified, we will also be able to compare the densities derived from our photogrammetry-based method, with literature density values for meteorites of the same type as the ones recovered by the Lost Meteorites of Antarctica team to assess the usefulness of the method.

One of the potential drawbacks of our method is that it can be fairly time consuming, taking several days to carefully photograph, and computationally process a meteorite from start to finish. Furthermore, the method may be challenging to undertake on highly reflective metallic samples – the software relies on identifying matching features in different pictures, and so a sample that predominantly reflects light might cause issues.

However, it is possible to make high fidelity models of meteorites of a range of a size, shape and colours. These can be useful curational tools and should also provide a dataset of information about the samples that would otherwise be difficult to attain whilst maintaining the pristine nature of the samples.

This study was the topic of a 2021 LPSC abstract which you can find here. You can find the various models we’ve made dotted about the individual meteorite information pages from the first season, or you can find a selection of them below!

UK Antarctic Meteorite Classification – the process

The first of the UK Antarctic meteorites have been classified! Nine rocks retrieved from the Hutchison (HUT) and Outer Recovery (OUT) icefields have been approved and published by the Meteoritical Bulletin. For details of these, please see this table and follow the links.

How were they classified?
The rocks collected in Antarctica were shipped frozen to the UK and kept in temperature monitored freezers. Each rock was thawed in an exisccator chamber to minimise any chemical reaction with residual ice; any ice present should sublimate straight to gas from the solid phase. After thawing, the rocks were all individually weighed and photographed. Measurements were taken of the rock’s magnetic susceptibility and electrical conductivity (see this previous blog post by Tom Harvey, as these properties can give a provisional indication of their possible classification.

Some of the meteorites were chosen to undergo computerised tomography (CT) scanning and photogrammetry. CT-scanning gives a 3D image of the interior of the rock. This provided compositional information and helped us to choose where to attempt to break or cut the rock. Photogrammetry allows a full 3D surface rendering of the meteorite to be made. For more details of this work, please see Tom’s LPSC conference presentation.

Tom Harvey in the curation lab imaging one of the meteorite samples. Photo: KJoy

Where there were no natural crumbs or fragments of material for further analysis, each rock was split with rock splitters, keeping them inside their sterile bag so that the only contact was with the stainless steel blade. A few meteorites and some of the fragments from the rock splitters were cut with a low speed saw to ensure the material does not get hot enough to cause any alteration.

Fragments were weighed, photographed and then made into epoxy blocks. These have to be polished to a very flat surface, in order to be able to examine the chemical composition using a scanning electron microscope (imaging system) and electron microprobe (used to determine mineral chemistry).

The scanning electron microprobe provides greyscale images (see left below), where the brightness corresponds to the differences in atomic number (number of protons) of the different elements. For example, iron, with an atomic number of 26, will be much brighter compared to sodium, with an atomic number of 11. It can also be used to quantify the difference in this brightness to get an idea of the relative abundance of each element and likely mineral. We use the scanning electron microscope first to get an image and element maps of the whole section (see right image below).

Following this, around 30-40 spots (points) are selected for measurement with the electron microprobe as this allows for more precise and accurate quantification of the mineral composition. In the element map above, the silicate minerals shown in green are usually olivine, and the minerals in light blue are usually pyroxene. The iron content of olivine and pyroxene varies and this is used to distinguish ordinary chondrites between the “H”, “L”, and “LL” classifications (check out where these meteorites sit within the family tree here).  “H” chondrites have the highest iron metal content, but lower iron oxide in pyroxene and olivine. “L” chondrites have lower iron and less metal but higher iron oxide in pyroxene and olivine, whereas “LL” have the lowest total iron but the highest iron oxide in pyroxene and olivine.

Graph showing the iron oxide abundance in pyroxene (Fs) against the iron oxide abundance in olivine (Fa). Yellow crosses show the data collected for five UK Antarctic meteorites, superimposed on a graph of values recommended as distinguishing the H, L and LL ordinary chondrite groups for the Nomenclature committee (Grossman & Rubin, 2006).

Meteorites classified!

We have news…. its a big day for the project as we have our first batch of meteorites that have been formally classified by the Meteoritical Society Nomenclature committee and have now been published in the Meteoritical Bulletin Database!

A list of the newly classified meteorites can be found here , and you can click on each meteorite name to learn more and see some pictures of the samples. So far all of those classified from our 1st field season come from parent bodies in the asteroid belt: all are undifferentiated ordinary chondrite types. This means that they come from some from asteroids that represent some of the earliest Solar System building block rocky material that never got big enough to completely melt (hence they are undifferentiated), but they are all are from quite a common type of meteorite group (the ordinary chondrites). So far all the types classified are stony and not metal types – meaning that they are dominantly made up of silicate minerals rather than metal. In case you get lost with all the terms used – an overview of the different types of meteorites can be found at

The first classified batch include nine meteorites: two were recovered from from the Hutchison Icefield area (these ones are called HUT), and seven from the Outer Recovery icefield area (these ones are called OUT). The number after the acronym name specifies the particular sample type. If you want to read more about the names of icefields we visited you can read here

This has been the cumulation of a lot of hard work from the field search teams from the 1st 2018-2019 field season (Julie Baum and Katie Joy) and logistics support personnel, the BAS cargo transfer team, the local meteorite lab and classification team – lead by Jane MacArthur with help from Thomas Harvey, Rhian Jones and Katie Joy. A huge thanks to the local analytical lab leads who have kept the instruments we use to image the samples and determine their chemistry (Lewis Hughes and Jon Fellowes), those who support the labs we use to prepare our samples (John Cowpe and Lydia Fawcett) and appreciate key advice from Andrew Smedley, Romain Tartese and Geoff Evatt. Thanks also to all the external help we have had from the Natural History Museum staff in helping these efforts, and to the Meteoritical Society Nomenclature team and Meteorite Bulletin teams for reviewing, approving and sharing the samples’ new names.

You can also read a blog from Jane on the lab curation approach where she will talk about how we go from picking up a sample in the field to working out what type of meteorite it represents.

We also have more samples under review by the nomenclature team so will announce what else we have found in the near future… stay tuned for more meteorites to come…

Photo of the largest sample found in season 1 – now called OUT 18021 (or still affectionately referred to as the melon on account of its large size). the scale cube is 1 cm in size. Image: Lost Meteorites of Antarctica / The University of Manchester

Research progress and LPSC 2021 conference presentation

We are working hard to classify the meteorites collected in Antarctica and will update you very soon with some news about what we have found.

Tom Harvey, who is an STFC student working on investigating the physical properties of the collection has some new results out which will be presented at the 2021 Lunar and Planetary Science Conference next week. His abstract citation is: T. A. Harvey, J. L. MacArthur , K. H. Joy, R. H. Jones (2021) None-destructive determination of the physical properties of Antarctic meteorites. 52nd Lunar and Planetary Science Conference 2021 (LPI Contrib. No. 2548)

His iposter (a new type of interactive conference poster) can be viewed at and has some amazing sneak previews of the meteorites captured through his photogrammetry technique.

Sledge Victor Over and Out

Katie Joy | 21 Jan 2020

The last few days have been somewhat manic to say the least. A final search on the 17th Jan didn’t yield any more meteorites, though we finished off the southern ice field and could put the doos (skidoos) to bed.

End of season thumbs up selfie from the two remaining Sledge Victor field party members (Katie in the stormtrooper mask at left, Taff in his duck beak mask at right). [Credit: Katie Joy]

A weather window then opened up across the Ronne Ice Shelf meaning that a plane was quickly dispatched from Rothera to come out to our field site at Outer Recovery to collect fieldguide Taff and I. We had a busy day of packing up camp, building and finalising the depots to be left over the Antarctic winter, sorting out all the kit to be brought back to Rothera.

Evening sun at our field site just before we broke camp. [Credit: Katie Joy]
Kelvin-Helmholtz clouds forming in the area, indicative shearing winds. [Credit: Katie Joy]

The weather was quite changeable in the day, with at one point snow blowing across the ice surface under 25 knot winds (not ideal for landing a plane when you need to see the skiway contrast). However, the Otter landed at about 10 pm on the 18th Jan with pilot Ian and co-pilot Callam, uplifting us back west, where we had a late night camping out in a mountain tent on Berkner Island. The air was still, but cold with our hair freezing up turning us grey, and the surface was snowy and looking like a million sugar lumps. The next morning on the 19th we departed for Rothera via Fossil Bluff, landing around 7 pm.

Flying back over the Peninsula – mountain ranges emerge out of the ice. [Credit: Katie Joy]
Melt ponds forming as the sea ice melts near Fossil Bluff. [Credit: Katie Joy]

Everything was rapidly unloaded from the aircraft and shifted to various parts of the base to be organised — the meteorites to the freezer, the rubbish to the rubbish centre, our science cargo to its storage area be sorted, all the field gear to the Fuchs building (sorry guys for making it a mess). Utterly overwhelming to see so many people after the relative quietness and tranquillity of the field. Finding our rooms, quick shower, making it to the dining hall (just) for the end of service (lamb roast – amazing). I was scheduled on the Dash 7 flight north to Chile for 9 am the next morning on the 20th…  so had to run around to organise all of my personal kit separating it from the BAS borrowed field kit and making sure things were washed (sorry to my roommate Sarah who’s bedroom was suddenly inundated with stinking clothes and four bags of stuff tipped out on the floor – I hope the smell of kerosene and field grime is not lingering) and the science cargo to be shipped back north later this month, to be ready to leave. Ahhhhh… finally got a beer at the end of a long day. Then the next morning saying goodbye to people, heading north on the Dash, dinner in Punta, an early night and collection at 4 am today for the next flights back to the UK via Santiago and Sau Paulo.

Flying over the Andes on route out of Santiago airport. [Credit: Katie Joy]

So yes, its been a bit mad for the last few days and I am missing life of being at Outer Recovery whizzing around the ice spotting meteorites. Antarctica grabs you (well it has certainly has got to me) and doesn’t let you go — hopefully I will get a chance to come back someday to continue the search for more space rocks on the ice.

It has been amazing that in just two field seasons with such small teams we have collected over 100 surface stones for future scientific study by the cosmochemistry community and I am very proud of what we have achieved and look forward very much to finding out what types of meteorites we have collected. Over to the laboratory and curation team now for the next phase of the science story, and hopefully we can continue to source more funding and the support of BAS to get back out to the ice in the next few years to continue our scientific success.

Saying goodbye to our fieldsite. [Credit: Katie Joy]

More blogs posts to come when we have results in from the last season’s meteorite haul, and to update everyone on our science research paper outcomes.

Some thanks and shout outs from me at this stage:

  • The rest of the Sledge Victor Manchester fieldteam — Geoff, Wouter, and Romain who fought a determined fight with the metal detector panels, and found some great meteorites during surface search days. To the story of 118-218-119-119alpha.
  • Andy Smedley, our Man back in Manchester, who has been receiving our emails from the field to post the blog. [BTW – we named the 3rd blue detector panel sledge Sledge Smedley (mentioned in this previous blog) in his honour at not having him with us in Antarctica]. Whilst Sledge Smedley only had a few days out and about, he lived his life to the full bouncing around and at least still has an intact bottom.
  • The Twin Otter flight teams (Mark, Ian, Dutch, and Dave) and co-pilots from Rothera and Halley who have come out to visit us this season and help get us and plane fuel across the enormity of the continent. The Rothera field operations managers who work 3-d chess to try and get everyone in the right place on the right day working around the ever changeable weather. The Rothera science coordinator Maz who has been so brilliant in helping out with requests for boxes, getting our cargo together for shipment, and just being completely fab. Everyone at Rothera and Halley who works hard to just get stuff done.
  • And a special thanks to our wonderful team of field guides Julie, Taff and Rob who have kept us safe, organised camp, provided great chats and moral, and have helped us to find the meteorites we have collected. Thanks guys for putting up with us all for the different parts of the project you have worked on this year and last, its been a privilege to spend time with you.

What we are up to in Antarctica…

Katie Joy | 30 Nov 2019

If you have been following the blog for a while then hopefully you will have seen the growth of our Lost Meteorites of Antarctica project from its infancy through to having a team of four people deployed to search for meteorites in Antarctica. If you are new to the blog (welcome!) you can read down the a couple of posts ago to see Geoff’s overview of the season’s plans and how we got here for some background…

The Lost Meteorites project team 2019-2020 season: from left Katie, Romain, Geoff and Wouter rubbing the Magellen’s foot in Punta Areas for good fortune in fair weather!

The Lost Meteorites of Antarctica project is an interdisciplinary science investigation bringing together mathematicians, electronic engineers, cold weather specialist engineers and meteoriticists (scientists who study meteorite samples), working with a large team of amazing people at the British Antarctic Survey to help support us and deploy us out to our field site. You can find out more about the team here. Currently four of us (Geoff, Katie, Wouter and Romain) are based at Rothera Research Station, the British Antarctic Survey’s largest crewed station in Antarctica getting prepared to get out to our field site (more about life on the station in the next couple of posts).

You can find out more about the science of what we are up to by heading over to the Science tab and about the science of meteorites here (what do we hope to find from all the rocks we collect?). Having already recovered tens of meteorites (we estimate 36 at this stage*) from the surface of the ice last field season, the challenge is on to collect more this time around as well as trying to locate iron-rich meteorites that are buried within the ice.

Location of Rothera Research Station in relation to the South American peninsula and Punta Areas in Chile; our departure city.

Thanks to those at Rothera who are taking good care of us — from the chefs who are cooking plentiful amazing meals, to our field guides Taff and Rob who have been helping get our kit together and train us for what to expect, the doctors training us in field medical techniques, the field and science operation leads Al and Maz who are working hard to put together the logistics to get us out to the field and are drawing on the skills of weather observation and forecast teams to help understand when the weather is a go for launch…

We likely have about another week or so here on station to get our metal detection system checked out and to finish off our training before we transfer out to the field (although as always, with Antarctica field campaigns, anything is controlled by the weather, so we will wait and see what happens…).

** more on what we found last season later on… Our team back in the UK are working hard to prepare and classify the samples as the team down here are working on finding them more rocks to play with!

Visiting new field sites and a new skidoo

Katie Joy | 08 Jan 2019

We have been a week in the field now, with a few search days under our belts and three meteorites in the bag. It has been pretty warm here — in the last couple of days in the sun the air is between 0 and 5°C — really balmy with very little wind. There has been a mix of clear sunny skies and some high cloud as a system hangs around the area. When it clouds over here we lose contrast on the snow and ice surface and it becomes difficult to navigate between icefields. When it was cloudy yesterday we did a bit of a foot searching along the edge of our local icefield to see if we could spot any meteorites. We donned our boot chains to stop us from slipping around on the ice surface, when the sun shines there is a layer of water that starts to form on the surface making it very slippy. However, the recent snowfall from last week (or perhaps earlier in the season) has lightly covered up the surface in this particular spot, making it very challenging to spot much exposed surface blue ice and meteorites.

Taking in the field site [Credit: K H Joy]

We ventured further afield on Sunday, driving up to a large well-exposed (no snow cover) ice area close to a small nunatak (exposed mountain top) where we discovered our first meteorite samples of the season. Whoop whoop! When the sun shines and there is no wind and there are meteorites it is a pretty great day and it feels good to demonstrate that we are visiting meteorite stranding zones.

Meteorite and skidoo [Credit: K H Joy]

Alas later that afternoon we also had some skidoo issues, and despite some great remote trouble-shooting from the Halley and Rothera mechanical teams, and some in-field mech action from Julie, we needed a replacement, which arrived today. Thanks to all for the amazing response and helping get a new one out to us so quickly, and for Mark and Robbie for flying in the new ride and taking out the injured ‘doo’ (and for bringing in some fresh food!). Goodbye unlucky number 13, and hello number 11 — may you drive well for the rest of the field season. We plan to get back to work tomorrow and drive out to a new icefield — fingers crossed for some more meteorite discoveries and hopefully there won’t be much surface snow where we plan to visit.

It is amazing to live (albeit for a short time) in such a remote place — when there is no wind and you are lying in the tent at night it is so quiet and warm in the sleeping bag it is pretty hard to imagine that we are in the middle of Antarctica really (apart from being able to see your breathe as the tent cools down). We are eating well — are working our way through different types of rehydrated food options (sweet and sour chicken last night) and are trying to keep up with some of the comforts of home through improvised barista coffee making (it doesn’t work that well to be honest!), chocolate bars, and evening games.

Coffee making attempt [Credit: K H Joy]

PS Thanks Barbara for the Christmas present which was delivered to Julie in field today.
PPS Thanks Jess for the Rothera news in your letter 🙂

What do we want to do with the meteorites we find?

Katie Joy | 04 Jan 2019

Whilst we sit and wait for the weather to improve in the field it gives a good opportunity for a sciencey blog post about the meteorite science side of the project. If you take a look over at the main ‘Science’ tab and follow the links to the ‘Meteorite Science’ tab it should give you some background information about why meteorites are scientifically important.

As an overview — meteorites provide us with direct samples of other rocky Solar System bodies, and, therefore, we can use them as probes to answer lots of different questions about how our Solar System formed and changed with time. The type of question we ask depends on the type of meteorite that we are studying and the lab equipment that we can use. Hopefully, any samples we find will be worked on by lots of different scientists in the meteorite community who are specialists in their particular meteorite group or laboratory method. Some questions we can ask of meteorite samples include:

What types of stars existed in the local area before our Sun formed?

Tiny (micron-sized) mineral grains trapped within very primitive dusty meteorites provide hints to what was happening prior to the Sun forming. These presolar grains — often made of minerals like diamond and silicon carbide — are chemically distinct from any of the material we have found within our own Solar System. These chemical (isotopic) anomalies can be related to how these grains formed in other stars, before they were included in the starting materials of our own Solar System.

How old is the Solar System?

We can date the earliest minerals that formed in our Solar System using a range of mass spectrometry isotopic techniques. This technology means that we have a very good precision on the timing of the oldest solid materials to form around our Sun. These grains — called calcium aluminium inclusions — are found in carbonaceous chondrite meteorites and have ages of 4567 million years old (4.56 billion years). This is the reference point we have for understanding the timing of other major events that occurred like the formation of the planets and the Earth itself.

What types of planetary bodies existed early on in the Solar System at the time the planets were forming?

Meteorites provide us with an insight to the diversity, size and number of the earliest formed planetesimals (small planetary bodies) that would have grown through run away collisions to form larger bodies. Recent estimates suggest that the 60,000 or so meteorites we have in the collection originate from only ~110 parent bodies (mostly asteroid-like), when you relate different groups together. We know that some of these parent bodies represent the very earliest assemblages of dust that first formed around the Sun (take a look at the Osiris-Rex space mission and Hayabusa-2 mission that are currently en route to these types of asteroids ready to collect material to return to the Earth, others have come from bodies that must have been larger and were heated from the inside out by radioactive decay-driven heating. Some meteorites are completely unique examples of potentially quite large parent bodies that must have been >200 km in size and melted completely to differentiate into an iron-rich core, a silicate mantle and a silicate crust. These bodies may have remained intact to still exist as large bodies in the asteroid belt (we think that a group of meteorites likely originated from a very large asteroid called Vesta), others were smashed apart leaving smaller asteroids formed of just a part of an original larger one (the NASA Pschye mission hopes to visit an asteroid we think is made of iron-metal, like the iron meteorites we have in the sample collection, formed from a core of an early planetessimal body). Every meteorite we find has the potential to come from a previously recognised rocky planetary body, giving us the motivation to keep on collecting and studying the populations of bodies that exist in the asteroid belt and those bodies that have broken apart early in the Solar System’s history.

How did the Earth get its volatiles including water?

One of the big questions we have is how did the Earth form, what were its starting materials, and why is it similar and different to the other large rocky Solar System bodies (Mercury, Venus, the Moon and Mars). Meteorites help to chemically constrain the starting materials for the Earth, although we have no perfect chemical match to known meteorite groups — there is similarity to some of the enstatite chondrites, but we also need contributions of other starting chondritic groups as well. We also know that different asteroid groups likely later delivered some of the Earth’s highly siderophile element chemical component and also likely some of its volatiles (water and other elements) to help form our planet’s atmosphere and hydrosphere. We can compare and contrast the chemical makeup of the different meteorite groups to understand how much of Earth’s chemical budget is original, and how much has been added early in its history.

What is the geological history of the Moon?

We have about 300 stones of lunar meteorites that originated from the Moon. We know they are from the Moon as they are chemically similar to the samples that were collected by the Apollo missions. Each one potentially provides us with a new region of the Moon to study and has allowed us to identify new types of rock samples, and help test our ideas of how the Moon has geologically evolved through time. We have some meteorites that were formed very early on in the Moon’s history, others than were made in impact cratering events and some that were formed in volcanic eruptions.

What is the geological history of Mars?

To date we have not yet collected any Mars rocks by sending a spacecraft there and returning it to Earth (there are sample return missions planned for about 10-15 years’ time). Therefore, martian meteorites are our most direct way to investigate Mars’s past. We know that this group of samples come from Mars as the gas trapped within them matches that measured by orbiting satellites and the Mars Curiosity Rover. Most of the martian meteorites we have were formed in volcanic eruptions that occurred on Mars’s surface about 600 million years ago, and we have some older intrusive magmatic examples as well. One special meteorite — nicknamed Black Beauty — found in Northwest Africa, gives us insights to Mars’s volcanic and impact evolution over a very long period of time from before 4 billion years ago to as recently as 1.1 billion years ago.

In addition to these planetary science questions – meteorites in Antarctica can also provide an indication of the history of the ice flows they are sitting in, and give a constraint on the age of the ice itself. This allows us to potentially use meteorites as probes of very recent terrestrial cryosphere processes, allowing us to understand the history of Antarctic glaciers and ice flow movement.

Avoiding the Italian Job

Geoff Evatt | 19 Dec 2018

At the end of the Italian Job, the looted gold is left at the rear of a coach that dangles dangerously over a precipice; tangentially close, yet also so far away: “Hang on boys, I’ve got an idea….”. Well, I too have had an idea. Chainsaws. OK, so that might not have helped Michael Caine in his predicament, but hopefully it’ll help us should we locate any englacial meteorites.

2018-12-04_08-57-36 chainsaw training GWE small
Essential course material: chainsaw, underlying theory, vape… [Credit: G W Evatt]

To be ready for sawing out some meteorites in a year’s time, I will give it a practise this coming January down at the BAS base, Sky-Blu. (the chainsaw bar length is 40 cm, the meteorites could be 50 cm deep: hmmm). And before I can even practise in the field, I was sent on a chainsaw course on an industrial estate in Chesterfield. Yes, it was a long long way from Antarctica, but it was freezing and the corrugated iron all around had a certain monotonous colouring, so maybe that will all come in useful. More importantly, I learned a lot about fixing basic chainsaw issues, how to sharpen chains, and how to cut logs the correct way (I’ve done a reasonable amount of chainsawing at home, but now I know sooo much more). The course instructor, James, also gave good suggestions as to how to cut ice and deal with the cold. In short, I feel much more prepared and confident about using the saw down there.

2018-12-04_10-32-06 chainsaw training GWE small
Tools of the trade. [Credit: G W Evatt]

And what if it’s a total failure (as in does not let me extract lumps of ice)? Well, I’ve also sent down a farm-shop of ironmongery, saws and ice drills. Between these, I hope that we will find an efficient method that allows us to extract any iron meteorites we detect. After all I want be prepared and confident, and we don’t wan’t to face any Italian Job conundrums….

2018-12-04_14-02-45 chainsaw training GWE small
Practising for Antarctica [Credit: G W Evatt]

PS For those of you really into their chainsaws, I’ll be using battery powered DeWalt one. Whilst it cut the Chesterfield logs very effectively, it may be a totally different matter in the cold, in which case I’ll have to opt to using a petrol one instead next season.