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| Known as 'Northwest Africa (NWA) 11119,' it was found in a sand dune in Mauritania. Now, researchers have dated the record-breaking space rock as being 4.565 billion years old. |
The oldest-ever dated meteorite is helping scientists unravel the mystery of how our solar system was formed.
Known as 'Northwest Africa (NWA) 11119,' the baseball sized meteorite was found in a sand dune in Mauritania.
Now, researchers have dated the record-breaking space rock as being 4.565 billion years old.
Scientists believe the solar system was formed some 4.6 billion years ago when a cloud of gas and dust collapsed under gravity, possibly triggered by a cataclysmic explosion from a nearby massive star or supernova.
As this cloud collapsed, it formed a spinning disk with the sun in the center.
They hope the meteorite will shed new light on this process.
'The meteorite we studied is unlike any other known meteorite,' co-author Daniel Dunlap at Arizona State University's Center for Meteorite Studies said.
'It has the highest abundance of silica and the most ancient age (4.565 billion years old) of any known igneous meteorite.
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| At ASU's Center for Meteorite Studies, scientists and co-authors Dunlap and Wadhwa used inductively coupled plasma mass spectrometry in their Isotope Cosmochemistry and Geochronology Laboratory, which helped determine the precise formation age of the meteorite. The research confirmed that NWA 11119 is the oldest-ever igneous meteorite recorded at 4.565 billion years old. |
'Meteorites like this were the precursors to planet formation and represent a critical step in the evolution of rocky bodies in our solar system.'
The research on this meteorite, published today in Nature Communications, provides the first direct evidence that chemically evolved, silica-rich crustal rocks were forming on planetesimals within the first 10 million years of the solar system, prior to the assembly of the terrestrial planets.
The research began at the University of New Mexico (UNM) with a yet-to-be studied meteorite, called 'Northwest Africa (NWA) 11119,' that was found in a sand dune in Mauritania.
Using an electron microprobe and a computed tomography (CT) scan at UNM and NASA's Johnson Space Center facilities, lead author Poorna Srinivasan started to examine the composition and mineralogy of the rock.
Srinivasan noted the intricacies of NWA 11119 including its unusual light-green fusion crust.
'The mineralogy of this rock is a very, very different from anything that we've worked on before,' Srinivasan said.
'I examined the mineralogy to understand all of the phases that comprise the meteorite.
'One of the main things we saw first were the large silica crystals of tridymite which is similar to the mineral quartz.
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| The rock is lighter in color than most meteorites and is laced with green crystals, cavities and quench melt, a type of rock texture that suggests rapid cooling and is often found in volcanic rocks which cool rapidly or 'quench' when brought to the surface quickly. |
'When we conducted further image analyses to quantify the tridymite, we found that the amount present was a staggering 30 percent of the total meteorite — this amount is unheard of in meteorites and is only found at these levels in certain volcanic rocks from the Earth.'
The chemical composition ranges of ancient igneous meteorites, or achondrites, are key to understanding the diversity and geochemical evolution of planetary building blocks. Achondrite meteorites record the first episodes of volcanism and crust formation, the majority of which are basaltic in composition.
'This research is key to how the building blocks of planets formed early in the solar system,' said co-author Carl Agee, director of UNM's Institute of Meteoritics.
'When we look out of the solar system today, we see fully formed bodies, planets, asteroids, comets and so forth. Then, our curiosity always pushes us to ask the question, how did they form, how did the Earth form?
'This is basically a missing part of the puzzle that we've now found that tells us these igneous processes act like little blast furnaces that are melting rock and processing all of the solar system solids. Ultimately, this is how planets are forged.'
