Universität zu Köln

Hezel, Dominik C., Poole, Graeme M., Hoyes, Jack, Coles, Barry J., Unsworth, Catherine, Albrecht, Nina, Smith, Caroline ORCID: 0000-0001-7005-6470, Rehkaemper, Mark, Pack, Andreas, Genge, Matthew and Russell, Sara S. (2015). Fe and O isotope composition of meteorite fusion crusts: Possible natural analogues to chondrule formation? Meteorit. Planet. Sci., 50 (2). S. 229 - 243. HOBOKEN: WILEY. ISSN 1945-5100

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Abstract

Meteorite fusion crust formation is a brief event in a high-temperature (2000-12,000K) and high-pressure (2-5MPa) regime. We studied fusion crusts and bulk samples of 10 ordinary chondrite falls and 10 ordinary chondrite finds. The fusion crusts show a typical layering and most contain vesicles. All fusion crusts are enriched in heavy Fe isotopes, with Fe-56 values up to +0.35 parts per thousand relative to the solar system mean. On average, the Fe-56 of fusion crusts from finds is +0.23 parts per thousand, which is 0.08 parts per thousand higher than the average from falls (+0.15 parts per thousand). Higher Fe-56 in fusion crusts of finds correlate with bulk chondrite enrichments in mobile elements such as Ba and Sr. The Fe-56 signature of meteorite fusion crusts was produced by two processes (1) evaporation during atmospheric entry and (2) terrestrial weathering. Fusion crusts have either the same or higher O-18 (0.9-1.5 parts per thousand) than their host chondrites, and the same is true for O-17. The differences in bulk chondrite and fusion crust oxygen isotope composition are explained by exchange of oxygen between the molten surface of the meteorites with the atmosphere and weathering. Meteorite fusion crust formation is qualitatively similar to conditions of chondrule formation. Therefore, fusion crusts may, at least to some extent, serve as a natural analogue to chondrule formation processes. Meteorite fusion crust and chondrules exhibit a similar extent of Fe isotope fractionation, supporting the idea that the Fe isotope signature of chondrules was established in a high-pressure environment that prevented large isotope fractionations. The exchange of O between a chondrule melt and an O-16-poor nebula as the cause for theobserved nonmass dependent O isotope compositions in chondrules is supported by the same process, although to a much lower extent, in meteorite fusion crusts.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Hezel, Dominik C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Poole, Graeme M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hoyes, Jack UNSPECIFIED UNSPECIFIED UNSPECIFIED Coles, Barry J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Unsworth, Catherine UNSPECIFIED UNSPECIFIED UNSPECIFIED Albrecht, Nina UNSPECIFIED UNSPECIFIED UNSPECIFIED Smith, Caroline UNSPECIFIED orcid.org/0000-0001-7005-6470 UNSPECIFIED Rehkaemper, Mark UNSPECIFIED UNSPECIFIED UNSPECIFIED Pack, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Genge, Matthew UNSPECIFIED UNSPECIFIED UNSPECIFIED Russell, Sara S. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-414060
DOI:	10.1111/maps.12414
Journal or Publication Title:	Meteorit. Planet. Sci.
Volume:	50
Number:	2
Page Range:	S. 229 - 243
Date:	2015
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1945-5100
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language OXYGEN; IRON; FRACTIONATION; RESERVOIRS; POTASSIUM Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/41406