Treasure map leads scientists to a 7.6-kilogram meteorite in Antarctica

Scientists recently discovered five meteorites in Antarctica. And one in particular stands out. It is a specimen weighing no less than 7.6 kilograms.

It is a unique finding, says researcher Vincienne Debay – affiliated with the Free University of Brussels saintias. “It is very rare to find such a huge meteorite.” And while such a large space rock doesn’t have to be more scientifically exciting than a small rock, scientists are very happy about the discovery. “Size doesn’t necessarily matter when it comes to meteorites, and even micrometeorites can prove to be of great scientific value,” said researcher Maria Valdez of the University of Chicago. “But discovering such a huge meteorite is very rare and exciting.”

Antarctica
Researchers discovered the large space rock — and four smaller specimens — in Antarctica, it’s said. This is – despite the often harsh conditions – one of the best places to find meteorites. There are three reasons for this. First of all, the dark stones stand out well against the light ice. In addition, it is particularly cold, so that meteorites are well preserved and hardly weathered. Finally, the Continent has the gift of presenting large numbers of meteorites in certain places, as it were, on a silver platter (see box).

focus mechanism
In 1969, scientists discovered the first meteorites in the so-called “blue ice regions” in Antarctica. While doing so, they also come across a previously unknown concentration mechanism that ensures that large numbers of meteorites are up for grabs in certain parts of Antarctica. How exactly does this work? When meteorites fall on Antarctica, they are soon covered with a layer of snow – under the influence of new layers of snow – it is compacted and a new layer of ice is formed. The meteorite gets stuck in that ice layer and flows with the ice – under the influence of gravity – towards the coast. Part of the ice will easily reach the coastal waters and melt there, so that the meteorite will eventually end up at the bottom of the sea. But some glacial currents face barriers: mountains that push ancient ice sheets—which contain meteorites—to the surface. And where that happens, meteorological processes also often play a role in ensuring that the ancient ice sublimates, so that the meteorites really get “loose” on the surface. Because of their blue color, caused by all the air bubbles being compressed and replaced by large ice crystals that poorly absorb blue light, these areas are also referred to as “blue ice areas”.

treasure map
The 7.6-kilo meteorite was found in the blue ice region. The researchers opened up the search for meteorites in this region by pointing to a real “treasure map”. It was developed last year by Belgian researchers. Because although the concentration mechanism discovered in 1969 has already led to the discovery of more than 45,000 meteorites in the Antarctic, the experiment has also shown that meteorites are not well represented in every blue ice region. This is why the Belgian researchers decided to investigate why the blue ice region is a suitable location for meteorites, and on this basis make a “treasure map” of the most promising blue ice regions as it is very likely that thousands of meteorites are still waiting to be discovered. “It involves more than 600 regions that vary in size from a few square kilometers to hundreds of square kilometres,” Tolnar said last year. Saintias.

useful
And for the first time, researchers recently traveled to Antarctica armed with that treasure map to search for meteorites in one of the distinctive regions of blue ice. And so successfully. “The treasure map has proven to be really useful,” says Debayle.

analysis
The five meteorites recovered will be investigated in the near future. “For now, they’re still in the fridge,” says Debayle. “The first step now is to let them melt. But because meteorites always have ice and snow and you want to prevent that from turning into liquid water affecting the meteorite, we’re going to melt the ice in a vacuum. Then the ice and snow will go straight into the gas phase.” Once done, it’s time for the next step. “Check which family the meteorites belong to.” Once this becomes clear, follow-up studies may also be planned, depending on the type of meteorite. “An important research goal has always been to gain more insight into the formation of our solar system,” DeBaile says. “How our solar system evolved from a cloud of gas and dust to a system of worlds and asteroids is something we’ve been trying to understand for some time.” And meteorites can help with that; Some samples – the so-called “primordial meteorites” have hardly changed, if at all, since their formation, about 4.5 billion years ago, and so can tell us more about conditions in the young solar system.

Answer
As mentioned, the large space rocks now found in Antarctica don’t have to be any more valuable than the smaller specimens discovered by Depay and colleagues. “It really depends on what the meteorites look like inside,” DeBaile notes. But meteorites are all valuable anyway. “They all provide answers.”

However, the main questions – regarding the origin and evolution of our solar system – will not be immediately resolved by these five meteorites. Instead, you should view it more as a puzzle, of which we see more and more pieces falling into place – due in part to discoveries in Antarctica. No wonder recent discoveries are hungry for more and researchers can’t wait – armed with a treasure map – to find more Antarctica meteorites. “Of course you want to collect all the meteorites,” Debayle confirms. However, this is still quite a task; Tolinar and his colleagues previously predicted – based on their treasure map – that at least 300,000 space rocks are still waiting to be discovered in Antarctica’s blue ice regions.