Universität zu Köln

Emmerton, Stacey, Muxworthy, Adrian R., Hezel, Dominik C. and Bland, Philip A. (2011). Magnetic characteristics of CV chondrules with paleointensity implications. J. Geophys. Res.-Planets, 116. WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 2169-9100

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Abstract

We have conducted a detailed magnetic study on 45 chondrules from two carbonaceous chondrites of the CV type: (1) Mokoia and (2) Allende. Allende has been previously extensively studied and is thought to have a high potential of retaining an extra-terrestrial paleofield. Few paleomagnetic studies of Mokoia have previously been undertaken. We report a range of magnetic measurements including hysteresis, first-order reversal curve analysis (FORCs), demagnetization characteristics, and isothermal remanent (IRM) acquisition behavior on both Mokoia and Allende chondrules. The Mokoia chondrules displayed more single domain-like behavior than the Allende chondrules, suggesting smaller grain sizes and higher magnetic stability. The Mokoia chondrules also had higher average concentrations of magnetic minerals and a larger range of magnetic characteristics than the Allende chondrules. IRM acquisition analysis found that both sets of chondrules have the same dominant magnetic mineral, likely to be a FeNi phase (taenite, kamacite, and/or awaruite) contributing to 48% of the Mokoia chondrules and 42% of the Allende chondrule characteristics. FORC analysis revealed that generally the Allende chondrules displayed low-field coercivity distributions with little interactions, and the Mokoia chondrules show clear single-domain like distributions. Paleointensity estimates for the two meteorites using the REMc and Preisach methods yielded estimates between 13 and 60 mu T and 3-56 mu T, respectively, for Allende and 3-140 mu T and 1-110 mu T, respectively, for Mokoia. From the data, we suggest that Mokoia chondrules carry a non-primary remagnetization, and while Allende is more likely than Mokoia to retain its primary magnetization, it also displays signs of post accretionary magnetization.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Emmerton, Stacey UNSPECIFIED UNSPECIFIED UNSPECIFIED Muxworthy, Adrian R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hezel, Dominik C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bland, Philip A. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-483231
DOI:	10.1029/2011JE003856
Journal or Publication Title:	J. Geophys. Res.-Planets
Volume:	116
Date:	2011
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	2169-9100
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language NATURAL REMANENT MAGNETIZATION; EARLY SOLAR-SYSTEM; CURVE FORC DIAGRAMS; CARBONACEOUS CHONDRITES; SHOCK MAGNETIZATION; METEORITES; FIELD; DEMAGNETIZATION; METAMORPHISM Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48323