Nanodiamantes não fornecem evidência única para um impacto de Dryas recente

terça-feira, dezembro 21, 2010

Nanodiamonds do not provide unique evidence for a Younger Dryas impact 

H. Tian a, D. Schryvers a,1, and Ph. Claeys b 

- Author Affiliations 

aElectron Microscopy for Materials Science (EMAT), Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium; and 
bEarth System Science, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium 

Edited by Mark H. Thiemens, University of California, San Diego, CA, and approved November 19, 2010 (received for review June 20, 2010) 


Microstructural, δ13C isotope and C/N ratio investigations were conducted on excavated material from the black Younger Dryas boundary in Lommel, Belgium, aiming for a characterisation of the carbon content and structures. Cubic diamond nanoparticles are found in large numbers. The larger ones with diameters around or above 10 nm often exhibit single or multiple twins. The smaller ones around 5 nm in diameter are mostly defect-free. Also larger flake-like particles, around 100 nm in lateral dimension, with a cubic diamond structure are observed as well as large carbon onion structures. The combination of these characteristics does not yield unique evidence for an exogenic impact related to the investigated layer. 

transmission electron microscopy, diffraction, spectroscopy 


1To whom correspondence should be addressed. 


Author contributions: D.S. and Ph.C. designed research; H.T. performed research; H.T., D.S., and Ph.C. analyzed data; and D.S. and Ph.C. wrote the paper. 

The authors declare no conflict of interest. 

This article is a PNAS Direct Submission.


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