cosmochemistry

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The Brain Scoop:
Fossil Meteorites! 

500 million years ago a collision between two asteroids threw one of them out of its rotation in the belt between Jupiter and Mars. Within a few tens of thousands of years the fragments of that meteor fell to earth and sank to the bottom of an ancient sea in modern-day Sweden. Over millions of years the mineralization process replaced many of the original elements in the meteorite, but thanks to some key identifying chemical markers our geologists and meteoriticists were able to determine that these specimens, excavated from a limestone quarry, are fragments of that ancient asteroid collision. 

The craziest part of all of this? Those fragments are still falling on earth today - in fact, one was found here in Chicago a few years ago, and after analysis it was matched to one of the fossilized fragments from Sweden. 

Separated by unthinkable distances in space and more than 500 million years, they’re reunited together again right here at The Field Museum. Now tell me that isn’t a story of star-crossed lovers. 

Scientists Solve Mystery of Odd Patterns of Oxygen in Solar System’s Earliest Rocks

Cosmochemists at the University of California, San Diego, have solved a long standing mystery in the formation of the solar system: Oxygen, the most abundant element in Earth’s crust, follows a strange, anomalous pattern in the oldest, most pristine rocks, one that must result from a different chemical process than the well-understood reactions that form minerals containing oxygen on Earth.

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This was the project that I worked on with my undergraduate research lab supervisor and lab co-worker. I’m pleased to know that the ‘doom machine,’ as it was called in the lab and that I performed tests on, was able to successfully do what it was intended to do! :)

Over the last few months, “Hipster Cosmochemist”  has become a Thing, which basically amounts to a caricature of me with my wayfarer glasses and scarf and overlarge cardigan, spouting gems like: 

“I liked the solar nebula before it cooled.”

“Yeah, it’s a pretty niche field… You’ve probably never heard of it.”

“My favorite meteorites are carbonaceous chondrites, because they're organic.

"I think later-forming planetary material is superior, it’s recycled.”

“Oxygen fraction is just so great, I love how it’s truly INDIE(pendant of mass)!”

“I feel like I was born 4.567 billion years too late, you know?”

“I only care about Asymptotic Giant Branch stars, all of the others are too Main Sequence.”

phys.org
Reexamination of Allende meteorite reveals isotopic evidence of supernova

A combined team of researchers has found isotopic evidence of a supernova inside of a meteorite that fell to Earth in 1969. In their paper published in Proceedings of the National Academy of Science, the team describes how isotopes found in the Allende meteorite differ from those found on Earth or on the moon, suggesting they came directly from a supernova rather than from a debris field that followed.

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We’ll mostly stick to pictures of minerals, but every once in a while we’ll tell you a little about some of the amazing people in the field of mineralogy. 

First up is Lawrence Grossman, Professor of Cosmochemistry at the University of Chicago.  His work has focused on the order of condensation of elements in the early solar system, and he contributed to the discovery of mass independent fractionation of isotopes in the Allende Meteorite.  He’s also done analyses on moon rocks from Apollo 15 and on Comet Wild-2, which was delivered to Earth from NASA’s Stardust mission.  

His contributions to mineralogy have been recognized by numerous awards as well as a pyroxene named after him: Grossmanite (CaTiSiAlO6), which can be found in meteorites, and was first observed in Allende.

Bonus facts: the Allende Meteorite contains some of the oldest known matter (it’s over 287 million years older than the oldest rock on Earth) and it provided amazing new insights into the early conditions of the solar system.


Sources: 1, 2, 3