The arrows point to suspected mineralized microbially-mediated biosignatures in the ALH-77005 meteorite. – Comparison of similar results of Mezö-Madaras, Mócs, Knyahinya, all of which suggest biogenicity on Mars, according to these authors. – Bioessential elements and carbon isotope data. – Possible biosignatures determined by optical microscopy and by FTIR-ATR. – Possible filamentous iron-oxidizing bacteria found in shock melt pocket of shergottite. Overall, the highlighted findings from ALH-77005 as listed in the paper include: Our study proposes the presence of microbial mediation on Mars. The other signatures for biogenicity of ALH-77005 are strong negative delta-c-13, enrichment of iron, manganese, phosphorus and zinc in shock melt support scenario. The possible biosignatures are found next to opaque minerals and inside shock melt pockets, which are the result of shock and fracturing during the meteorite’s encounter with Earth. They found embedded spherical and thread-like structures, material that represent possible biosignatures, that is, the mineralized remains of ancient microbes and their alteration of minerals in the rock. The argon was found to be the same as argon traces in the meteorites.įor this new study, the researchers took a very thin section sample of the meteorite and studied it using optical microscopy for microtextures – microscopic texture patterns – and FTIR-ATR microscopy. The Curiosity rover confirmed the connection between Mars itself and these meteorites found on Earth in October 2013, after the rover analyzed argon in Mars’ atmosphere. How do we know these meteorites came from Mars? Like other Martian meteorites, ALH-77005 is known to have originated on Mars because it has a composition similar to rocks and atmosphere gases analyzed by Mars spacecraft. About three-quarters of all known Martian meteorites are shergottites. It is a shergottite meteorite – composed of igneous rock – named after the Shergotty meteorite, which fell at Sherghati, India (formerly spelled Shergotty), in 1865. The meteorite is estimated to be 175 million years old. The Japanese National Institute of Polar Research mission (1977-1978) discovered the ALH-77005 meteorite in the Allan Hills in Antarctica in 1977. Image via NASA/Johnson Space Center/Wikipedia. The ALH-77005 Martian meteorite, found in Allan Hills, Antarctica in 1977. Another view of the same thin slice from the meteorite in polarized light. The research will also be of interest to planetologists, experts of meteorite and astrobiology as well as researchers of the origin of life, and to the general public since it offers an example of a novel aspect of microbial mediation in stone meteorites. Our work is important to a broad audience because it integrates planetary, Earth, biological, chemical and environmental sciences and will be of interest to many researchers in those fields. According to lead author Ildiko Gyollai from HAS Research Centre for Astronomy and Earth Sciences in Budapest: The peer-reviewed findings were published online in the journal Open Astronomy on March 28, 2019. The material in the meteorite is similar to that produced by iron-oxidizing microbes on Earth. Now, a research team in Hungary has found another tantalizing clue – mineralized and filament-like organic material embedded in a Martian meteorite – ALH-77005 – from the Allan Hills region of Antarctica. Such a discovery would have profound implications for the search for life elsewhere in the solar system and on exoplanets orbiting other stars. Has there ever been life on Mars? We are still awaiting a definitive answer to that long-standing question, although evidence has continued to build that there may indeed have been little critters – albeit most likely microscopic – in or below those distant red sands. The melt pocket region, inside the rectangle is where scientists found evidence for microbial mediation. Thin slice of the martian meteorite ALH-77005.
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