ExomatrixTV
16th September 2014, 08:31
A conspicuous biomorphic ovoid structure has been discovered in the Nakhla martian meteorite, made of nanocrystalline iron-rich saponitic clay and amorphous material. The ovoid is indigenous to Nakhla and occurs within a late-formed amorphous mesostasis region of rhyolitic composition that is interstitial to two clinopyroxene grains with Al-rich rims, and contains acicular apatite crystals, olivine, sulfides, Ti-rich magnetite, and a new mineral of the rhoenite group. To infer the origin of the ovoid, a large set of analytical tools was employed, including scanning electron microscopy and backscattered electron imaging, wavelength-dispersive X-ray analysis, X-ray mapping, Raman spectroscopy, time-of-flight secondary ion mass spectrometry analysis, high-resolution transmission electron microscope imaging, and atomic force microscope topographic mapping. The concentric wall of the ovoid surrounds an originally hollow volume and exhibits internal layering of contrasting nanotextures but uniform chemical composition, and likely inherited its overall shape from a preexisting vesicle in the mesostasis glass. A final fibrous layer of Fe-rich phases blankets the interior surfaces of the ovoid wall structure. There is evidence that the parent rock of Nakhla has undergone a shock event from a nearby bolide impact that melted the rims of pyroxene and the interstitial matter and initiated an igneous hydrothermal system of rapidly cooling fluids, which were progressively mixed with fluids from the melted permafrost. Sharp temperature gradients were responsible for the crystallization of Al-rich clinopyroxene rims, rhoenite, acicular apatites, and the quenching of the mesostasis glass and the vesicle. During the formation of the ovoid structure, episodic fluid infiltration events resulted in the precipitation of saponite rinds around the vesicle walls, altered pyrrhotite to marcasite, and then isolated the ovoid wall structure from the rest of the system by depositing a layer of iron oxides/hydroxides. Carbonates, halite, and sulfates were deposited last within interstitial spaces and along fractures. Among three plausible competing hypotheses here, this particular abiotic scenario is considered to be the most reasonable explanation for the formation of the ovoid structure in Nakhla, and although compelling evidence for a biotic origin is lacking, it is evident that the martian subsurface contains niche environments where life could develop. Key Words: Biomorph—Clays—Search for life (biosignatures)—Martian meteorites—Hydrothermal systems. Astrobiology 14, 651–693.
http://online.liebertpub.com/doi/full/10.1089/ast.2013.1069
Martian meteorite yields more evidence of the possibility of life on Mars
15 Sep 2014
A tiny fragment of Martian meteorite 1.3 billion years old is helping to make the case for the possibility of life on Mars, say scientists.
http://newsadmin.manchester.ac.uk/newsimages/255/12797_large.jpg
Is there life on Mars? Image credit : NASA/JPL/MSSS
The finding of a ‘cell-like’ structure, which investigators now know once held water, came about as a result of collaboration between scientists in the UK and Greece. Their findings are published in the latest edition of the journal Astrobiology.
While investigating the Martian meteorite, known as Nakhla, Dr Elias Chatzitheodoridis of the National Technical University of Athens found an unusual feature embedded deep within the rock. In a bid to understand what it might be, he teamed up with long-time friend and collaborator Professor Ian Lyon at the University of Manchester.
Professor Lyon, based in Manchester’s School of Earth, Atmospheric and Environmental Sciences, said: “In many ways it resembled a fossilised biological cell from Earth but it was intriguing because it was undoubtedly from Mars. Our research found that it probably wasn’t a cell but that it did once hold water - water that had been heated, probably as a result of an asteroid impact.”
These findings are significant because they add to increasing evidence that beneath the surface, Mars does provide all the conditions for life to have formed and evolved. It also adds to a body of evidence suggesting that large asteroids hit Mars in the past and produce long-lasting hydrothermal fields that could sustain life on Mars, even in later epochs, if life ever emerged there.
As part of the research, the feature was imaged in unprecedented detail by Dr Sarah Haigh of The University of Manchester whose work usually involves high resolution imaging for next generation electronic devices ,which are made by stacking together single atomic layers of graphene and other materials with the aim of making faster, lighter and bendable mobile phones and tablets. A similar imaging approach was able to reveal the atomic layers of materials inside the meteorite.
Together their combined experimental approach has revealed new insights into the geological origins of this fascinating structure.
Professor Lyon said: “We have been able to show the setting is there to provide life. It’s not too cold, it’s not too harsh. Life as we know it, in the form of bacteria, for example, could be there, although we haven’t found it yet. It’s about piecing together the case for life on Mars – it may have existed and in some form could exist still.”
Now the team is using these and other state-of-the-art techniques to investigate new secondary materials in this meteorite and search for possible bio signatures which provide scientific evidence of life, past or present. Professor Lyon concluded: “Before we return samples from Mars, we must examine them further, but in more delicate ways. We must carefully search for further evidence.”
Notes for editors
The scientists’ findings A Conspicuous Clay Ovoid in Nakhla: Evidence for Subsurface Hydrothermal Alteration on Mars with Implications for Astrobiology Elias Chatzitheodoridis, Sarah Haigh, and Ian Lyon are published in Astrobiology, Vol. 14, No. 8 (http://online.liebertpub.com/toc/ast/14/8#utm_source=ETOC&utm_medium=e)
The work was supported by the Science and Technology Facilities Council.
Media enquiries to:
Katie Brewin/Aeron Haworth
Media Relations Officer
The University of Manchester
Tel: 0161 275 8387
Email: aeron.haworth@manchester.ac.uk (http://aeron.haworth.manchester.ac.uk)
http://www.manchester.ac.uk/discover/news/article/?id=12797
http://online.liebertpub.com/doi/full/10.1089/ast.2013.1069
Martian meteorite yields more evidence of the possibility of life on Mars
15 Sep 2014
A tiny fragment of Martian meteorite 1.3 billion years old is helping to make the case for the possibility of life on Mars, say scientists.
http://newsadmin.manchester.ac.uk/newsimages/255/12797_large.jpg
Is there life on Mars? Image credit : NASA/JPL/MSSS
The finding of a ‘cell-like’ structure, which investigators now know once held water, came about as a result of collaboration between scientists in the UK and Greece. Their findings are published in the latest edition of the journal Astrobiology.
While investigating the Martian meteorite, known as Nakhla, Dr Elias Chatzitheodoridis of the National Technical University of Athens found an unusual feature embedded deep within the rock. In a bid to understand what it might be, he teamed up with long-time friend and collaborator Professor Ian Lyon at the University of Manchester.
Professor Lyon, based in Manchester’s School of Earth, Atmospheric and Environmental Sciences, said: “In many ways it resembled a fossilised biological cell from Earth but it was intriguing because it was undoubtedly from Mars. Our research found that it probably wasn’t a cell but that it did once hold water - water that had been heated, probably as a result of an asteroid impact.”
These findings are significant because they add to increasing evidence that beneath the surface, Mars does provide all the conditions for life to have formed and evolved. It also adds to a body of evidence suggesting that large asteroids hit Mars in the past and produce long-lasting hydrothermal fields that could sustain life on Mars, even in later epochs, if life ever emerged there.
As part of the research, the feature was imaged in unprecedented detail by Dr Sarah Haigh of The University of Manchester whose work usually involves high resolution imaging for next generation electronic devices ,which are made by stacking together single atomic layers of graphene and other materials with the aim of making faster, lighter and bendable mobile phones and tablets. A similar imaging approach was able to reveal the atomic layers of materials inside the meteorite.
Together their combined experimental approach has revealed new insights into the geological origins of this fascinating structure.
Professor Lyon said: “We have been able to show the setting is there to provide life. It’s not too cold, it’s not too harsh. Life as we know it, in the form of bacteria, for example, could be there, although we haven’t found it yet. It’s about piecing together the case for life on Mars – it may have existed and in some form could exist still.”
Now the team is using these and other state-of-the-art techniques to investigate new secondary materials in this meteorite and search for possible bio signatures which provide scientific evidence of life, past or present. Professor Lyon concluded: “Before we return samples from Mars, we must examine them further, but in more delicate ways. We must carefully search for further evidence.”
Notes for editors
The scientists’ findings A Conspicuous Clay Ovoid in Nakhla: Evidence for Subsurface Hydrothermal Alteration on Mars with Implications for Astrobiology Elias Chatzitheodoridis, Sarah Haigh, and Ian Lyon are published in Astrobiology, Vol. 14, No. 8 (http://online.liebertpub.com/toc/ast/14/8#utm_source=ETOC&utm_medium=e)
The work was supported by the Science and Technology Facilities Council.
Media enquiries to:
Katie Brewin/Aeron Haworth
Media Relations Officer
The University of Manchester
Tel: 0161 275 8387
Email: aeron.haworth@manchester.ac.uk (http://aeron.haworth.manchester.ac.uk)
http://www.manchester.ac.uk/discover/news/article/?id=12797