Universität zu Köln

Palme, Herbert, Spettel, Bernhard and Hezel, Dominik ORCID: 0000-0002-5059-2281 (2014). Siderophile elements in chondrules of CV chondrites. Chem Erde-Geochem., 74 (3). S. 507 - 517. MUNICH: ELSEVIER GMBH. ISSN 1611-5864

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Abstract

New bulk compositional data for 34 Allende chondrules are presented. Whole chondrules were analyzed by instrumental neutron activation analysis (INAA). The new data set is evaluated together with older INAA data on Allende chondrules and recent INAA data on Mokoia chondrules. The Ni/Co ratios of 200 chondrules are close to the CI- or solar ratio. The chondritic Ni/Co ratios require an unfractionated chondritic metal source and set a limit to the fraction of metal lost from molten chondrules. The bulk chondrule Fe/Ni and Fe/Co ratios are more variable but on average chondritic. Iridium and other refractory metals have extremely variable concentrations in chondrules. High Ir chondrules have chondritic Ir/Sc ratios. They are dominated by CAI (Ca,Al-rich inclusion) components. Low Ir chondrules have approximately chondritic Ir/Ni ratios reflecting mixing with chondritic metal. In low Ir chondrules Ir correlates and in high Jr chondrules Ir does not correlate with Ni or Co. A large fraction of Ir may have entered chondrules in variable amounts as tiny grains of refractory metal alloys. Most Allende chondrules have Ir/Sc ratios below bulk meteorite ratios. Matrix must have a complementary high Ir/Sc ratio, as bulk Allende has approximately chondritic Ir/Sc ratio. Similarly, the high average Ir/Ni ratios of Allende chondrules must be balanced by low Ir/Ni ratios in matrix to obtain the bulk Allende Ir/Ni ratio, which is close to the average solar system ratio. More recent data on single chondrules from Allende by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and ICP-OES (Inductively Coupled Optical Emission Spectrometry) show the same trends as the INAA data discussed here. (C) 2014 Elsevier GmbH. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Palme, Herbert UNSPECIFIED UNSPECIFIED UNSPECIFIED Spettel, Bernhard UNSPECIFIED UNSPECIFIED UNSPECIFIED Hezel, Dominik UNSPECIFIED orcid.org/0000-0002-5059-2281 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-449564
DOI:	10.1016/j.chemer.2014.06.003
Journal or Publication Title:	Chem Erde-Geochem.
Volume:	74
Number:	3
Page Range:	S. 507 - 517
Date:	2014
Publisher:	ELSEVIER GMBH
Place of Publication:	MUNICH
ISSN:	1611-5864
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ALLENDE METEORITE; METAL; CONDENSATION; ORIGIN; CONSTRAINTS; COMPONENTS; INCLUSIONS; CHEMISTRY Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/44956