Tracing the oxygen isotope composition of the upper Earth's atmosphere using cosmic spherules

Molten I-type cosmic spherules formed by heating, oxidation and melting of extraterrestrial Fe,Ni metal alloys. The entire oxygen in these spherules sources from the atmosphere. Therefore, I-type cosmic spherules are suitable tracers for the isotopic composition of the upper atmosphere at altitudes...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Pack, Andreas, Höweling, Andres, Hezel, Dominik C., Stefanak, Maren T., Beck, Anne-Katrin, Peters, Stefan T. M., Sengupta, Sukanya, Herwartz, Daniel, Folco, Luigi
Format: Text
Language:English
Published: Nature Publishing Group 2017
Subjects:
Article
Antarc*
Antarctica
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5461487/
http://www.ncbi.nlm.nih.gov/pubmed/28569769
https://doi.org/10.1038/ncomms15702
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Summary:Molten I-type cosmic spherules formed by heating, oxidation and melting of extraterrestrial Fe,Ni metal alloys. The entire oxygen in these spherules sources from the atmosphere. Therefore, I-type cosmic spherules are suitable tracers for the isotopic composition of the upper atmosphere at altitudes between 80 and 115 km. Here we present data on I-type cosmic spherules collected in Antarctica. Their composition is compared with the composition of tropospheric O2. Our data suggest that the Earth's atmospheric O2 is isotopically homogenous up to the thermosphere. This makes fossil I-type micrometeorites ideal proxies for ancient atmospheric CO2 levels.

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