PSRD | CosmoSparks reports

Quick Views of Big Advances

about archive search subscribe glossary comments

Chondrule Formation

BSE image of chondrules in GRA 06100 showing analysis spots by D. Schrader etal. 2013.
In this backscatter electron image of chondrules in meteorite GRA 06100, red dots indicate locations of O-isotope analysis spots in a type-II chondrule and in a fragment of a relict-free type-II chondrule. Other labels are olv = olivine, rel = FeO-poor relict grain, mx = matrix, sulf = sulfide.
The origin of chondrules—the material from which they formed and their melting histories—has intrigued cosmochemists for decades and continues as an active research theme. Recent work by Devin Schrader (formerly at the University of Arizona and now at the University of Hawai‘i) and colleagues from Arizona, New York, and Hawai‘i, aims to constrain the formation conditions of the two main chondrule groups, designated type-I and type-II, to answer whether or how their origins are related. Schrader and coauthors have studied the oxygen-isotopic compositions and oxidation states of olivine in type-I and type-II chondrules from three Renazzo-like carbonaceous (CR) chondrites. The meteorite samples (GRA 95229, GRA 06100, and QUE 99177; collected by the U.S. Antarctic Search for Meteorites program), span a wide range of whole rock oxygen-isotopic compositions. Their detailed analyses of the major-and minor-element abundances and in situ oxygen-isotopic compositions of 21 chondrule olivines yielded interesting results, including:

pdf link, Chondrule Formation (pdf version)

·   Schrader, D. L., Connolly Jr., H. C., Lauretta, D. S., Nagashima, K., Huss, G. R., Davidson, J., and Domanik, K. J. (2013) The Foramtion and Alteration of the Renazzo-like Carbonaceous Chondrites II: Linking O-isotope Composition and Oxidation State of Chondrule Olivine, Geochimica et Cosmochimica Acta, v. 101, p. 302-327, doi: 10.1016/j.gca.2012.09.045.   [ abstract ]

For more:
·   Sakamoto, N., Seto, Y., Itoh, S., Kuramoto, K., Fujino, K., Nagashima, K., Krot, A. N., and Yurimoto, H. (2007) Remnants of the Early Solar System Water Enriched in Heavy Oxygen, Science, v. 317, p. 231-233, doi: 10.1126/science.1142021.   [ abstract ]
·   Schrader, D. L., Franchi, I. A., Connolly Jr., H. C., Greenwood, R. C., Lauretta, D. S., and Gibson, J. M. (2011) The Formation and Alteration of the Renazzo-like Carbonaceous Chondrites I: Implications of Bulk-Oxygen Isotopic Composition, Geochimica et Cosmochimica Acta, v. 75, p. 308-325, doi: 10.1016/j.gca.2010.09.028.   [ abstract ]

Written by Linda M. V. Martel, Hawai‘i Institute of Geophysics and Planetology, for PSRD.

[ About PSRD | Archive | CosmoSparks | Search | Subscribe ]

[ Glossary | General Resources | Comments | Top of page ]           + Share

January 2013