New meteorites need new names…

To be able to give the meteorites we have recovered a formal name we have to go through some procedures…

Dense meteorite stranding zones (areas where lots of meteorites are found) are awarded a name by the Meteoritical Society Nomenclature committee. The meteorites recovered from these areas are then named after these sites – for example the first recognised lunar meteorite Allan Hills (ALHA for short) 81005 is named after the Allan Hills icefield A in Antarctica. Thus, to be given a name we need the place that the meteorites are found to be called something!

Our issue is that the regions we visited in Antarctica had not been formally allocated names by the countries who administrate these areas. So we have gone through two different routes to formally assign names to the field sites we visited so that we can use the names of these geographical features in future research publications and use them to name the meteorites we recovered.

We are happy to announce that our two main field areas have been approved as the Outer Recovery Icefields in Dronning Maud Land by the Norwegian Polar Institute and Hutchison Icefield in Coats Land (British Antarctic Territory ) by the UK Antarctic Place-names Committee. Both of these field sites contain nunataks (mountain tops emerging from the ice), which have also been named after meteorite and meteor scientists (see below for details). The UK site names are included in the UK Antarctic Gazetteer (https://apc.antarctica.ac.uk/) and are available for use on all maps and charts and in all publications. They are also included in the Scientific Committee on Antarctic Research (SCAR) Composite Gazetteer of Antarctica (https://data.aad.gov.au/aadc/gaz/scar/ ).

These names have now also been approved by the Meteoritical Society as dense meteorite collection areas and we will be able to call the meteorites either OUT (for those collected at the Outer Recovery Icefields) and HUT for those collected from the Hutchison Icefield.

Regional context of the fieldsites for the Lost Meteorites of Antarctica project. See below for details of the two areas highlighted with black boaxes. Base map is Landsat Image Mosaic of Antarctica. Image: Katherine Joy.

Outer Recover Icefields Area

Outer Recovery Icefields. named because of its proximity to the Recovery Glacier found adjacent to the northern extent of the area. Link to online Norwegian record.

Halliday Nunatak (81°24’32.97″S, 18° 1’59.88″W): Located in the Outer Recovery Icefields. named after Canadian astronomer Dr Ian Halliday (1928-2018) who was a Canadian astronomer with expertise in meteor (asteroid and comet) delivery rates to the Earth. Link to online Norwegian record

Outer Recovery Icefield area showing locations of the nunatak and four separate blue ice fields. Base map is Landsat Image Mosaic of Antarctica overlain with high resolution Sentinel 2 image. Map scale is 1:250,000 Image: Katherine Joy.

Hutchison Icefield Area

Hutchison Icefield (81°30′ 30″S, 26°10’W): Named after British meteorite scientist Dr Robert Hutchison (1938-2007) who was the Curator of Meteorites at the Natural History Museum, London. He was Head of the Cosmic Mineralogy Research Programme at the NHM, and responsible for the national meteorite collection, one of the most significant meteorite collections in the world. Awarded the Gold Medal of the Royal Astronomical Society in 2002; asteroid 5308 named Hutchison by the International Astronomical Union. Named in association with names of pioneering meteoriticists grouped in this area. Link to online SCAR record.

Turner Nunatak (81°27′ 50.42″S, 26°24’48.88″W): Located in the Hutchison Icefield. Named after Professor Grenville Turner FRS (b. 1936) pioneering lunar and meteorite scientist, Emeritus Professor at the University of Manchester. He established the University of Manchester Isotope Cosmochemistry group and his pioneering work on rare gases in meteorites led him to develop the argon–argon dating technique that demonstrated the great age of meteorites and provided a precise chronology of rocks brought back by the Apollo missions. He was one of the few UK scientists to be a Principal Investigator of the Apollo samples during the time of the US manned Moon missions. Link to online SCAR record.

Pillinger Nunatak (81°34’40″S, 26°24’15″W): Located in the Hutchison Icefield. Named after Professor Colin Pillinger FRS (1943-2014), English planetary scientist who was a founding member of the Planetary and Space Sciences Research Institute at Open University in Milton Keynes, and through his career studied stable isotopes in Apollo Moon samples, martian meteorites and asteroidal meteorites. He was also the Principal Investigator for the British Beagle 2 Mars lander project. Link to online SCAR record.

Map showing Hutchison Icefield area with Turner nunatak to the north and Pillinger nunatak to the south. Karpenko massif is a region of disturbed ice named after a Russian Engineer Aleksei Illaryonovich Karpenko (1940-82). Base map is Sentinel 2 image. Image: Dr Adrian Fox (UK Antarctic Place-names Committee)

With many thanks to Dr Adrian Fox (UK Antarctic Place-names Committee), Dr Oddveig Øien Ørvoll of the Norwegian Polar Institute for all of their help with the naming of these regions and advice from Laura Gerrish at the British Antarctic Survey.

Meanwhile in Manchester…

13 Jan 2020

Readers will have seen and read about a lot of goings on “down south” in Rothera and at the Outer Recovery ice fields, and the results of the team’s searches at the field site near the Shackleton Mountains. This is only part of the story (though a key one)!

Back in Manchester the rest of the Lost Meteorites of Antarctica team have been busy, so we thought it only right that we give a brief overview of the work going on behind the scenes. Recently mentioned, Liam and John provided support to Wouter with the technical glitches and have of course been instrumental throughout the project from its initial design, build, lab testing and field testing.

Patches of blue ice at the base of cliffs in the Theron Mountains. Selecting the right spot is key to finding meteorites. [Credit: Romain Tartese]

In parallel with the detector system build, Andy has been working with lots of data analysis (using satellite datasets and climate model outputs) to figure out whereabouts the team was best searching for meteorites. Antarctica is a big place and meteorites are only found in a few spots. Sometimes people head out there to come back empty handed, so we wanted to do our best for last season to make sure we found a “blue ice area” that harboured meteorites. First of all, a selection of candidate sites were tracked down by Katie (before the current project was funded) and then reduced to a long-list of those accessible on a logistics basis with the help of BAS. Then, using a combination of estimates of snowfall (that tells us something about the rate at which meteorites accumulate in a given area), and the local surface ice flow and wind scouring (that tells about the rate of loss of meteorites), we came up with a prediction of what density of meteorites we expected across these candidate sites. That prediction enabled us to refine and rank our preferred areas for Katie to visit last year. Thankfully she and Julie Baum confirmed our estimates and found some meteorites! Once we had decided on particular areas, Andy was involved in making custom maps for the team’s GPSs from hi-res satellite imagery, more detailed estimates of which individual ice fields to return to (from the data and samples Katie collected last year), and the logistics involved in shipping and planning. At the moment he’s the main contact back in Manchester and has been responsible for posting updates sent through by satellite phone while Geoff, Katie, Wouter and Romain have been at the remote field site.

There’s lots of posts about trying to find meteorites on the blog, but once we find them — what happens to them? That job is being undertaken by Jane and Tom working with members of the isotope group.

Well, we’ve made sure the potential meteorites have all been collected following defined procedures to keep them as free from any contamination as possible, for example, they only come into contact with stainless steel equipment used to get them into polythene bags, and every sample is double-bagged. They are even kept at sub-zero temperatures throughout their journey back to the UK, giving us the best chance of keeping them in pristine condition for future science. Jane, working with Katie, Rhian Jones and with folks at the meteorite group at the NHM, has been working out the necessary steps for the preliminary examination plan for classifying the meteorites, to ensure the samples do not get contaminated, and that every stage of examination is thoroughly documented. In line with this, the first ten samples from last season have now been thawed and she is using “CT-scanning” to look inside the rock and get an initial idea of what it is made of, before deciding how to break or cut the sample. Small pieces will then be mounted on glass slides in order to examine them with microscopes so that they can be formally classified into their different classes.

The “light box” set up used to acquire the images for 3D photogrammetry scans. [Credit: Tom Harvey]

Now the first samples from last year’s reconnaissance trip have been defrosted, Tom has been working to scan the fresh sample exteriors with a technique called photogrammetry. Photogrammetry uses information in pictures of a sample (in this case a meteorite) which show overlapping surface features to position that bit of the sample in 3D space — meaning that we can generate an electronic 3D model of the sample! These models are really useful because they preserve a record of the sample exterior prior to analysis (or, if needs be, cutting), and mean that we can zoom in on parts of the surface that are particularly interesting, which is great for curation and initial characterisation purposes and gives a permanent record of what the meteorite looked like when it was found.

And as this post goes online, it sounds like this year’s samples might just be starting to make the long journey back to the UK… holding the promise of lots more interesting science.