Identification of a meteoritic component using chromium isotopic composition of impact rocks from the Lonar impact structure, India

1,2Berengere Mougel,1,3Frederic Moynier,4,5Christian Koeberl,6Daniel Wielandt,6Martin Bizzarro
Meteoritics & Planetary Science (in Press) Link to Article []
1Institut de Physique du Globe de Paris, Université Sorbonne Paris Cité, CNRS UMR7154, 1 rue Jussieu, 75238 Paris Cedex 05, France
2Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla No 3001, Querétaro, 76230 Mexico
3Institut Universitaire de France, 1 rue Descartes, 75231 Paris Cedex 05, France
4Department of Lithospheric Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
5Natural History Museum, Burgring 7, 1010 Vienna, Austria
6Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5‐7 DK‐1350, Copenhagen, Denmark
Published by arrangement with John Wiley & Sons

The existence of mass‐independent chromium isotope variability of nucleosynthetic origin in meteorites and their components provides a means to investigate potential genetic relationship between meteorites and planetary bodies. Moreover, chromium abundances are depleted in most surficial terrestrial rocks relative to chondrites such that Cr isotopes are a powerful tool to detect the contribution of various types of extra‐terrestrial material in terrestrial impactites. This approach can thus be used to constrain the nature of the bolide resulting in breccia and melt rocks in terrestrial impact structures. Here, we report the Cr isotope composition of impact rocks from the ~0.57 Ma Lonar crater (India), which is the best‐preserved impact structure excavated in basaltic target rocks. Results confirm the presence of a chondritic component in several bulk rock samples of up to 3%. The impactor that created the Lonar crater had a composition that was most likely similar to that of carbonaceous chondrites, possibly a CM‐type chondrite.


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