Zinc isotopic composition of iron meteorites: Absence of isotopic anomalies and origin of the volatile element depletion
Version of Record online: 23 DEC 2013
© The Meteoritical Society, 2013.
Meteoritics & Planetary Science
Volume 48, Issue 12, pages 2441–2450, December 2013
How to Cite
Chen, H., Nguyen, B. M. and Moynier, F. (2013), Zinc isotopic composition of iron meteorites: Absence of isotopic anomalies and origin of the volatile element depletion. Meteoritics & Planetary Science, 48: 2441–2450. doi: 10.1111/maps.12229
- Issue online: 23 DEC 2013
- Version of Record online: 23 DEC 2013
- Manuscript Accepted: 12 OCT 2013
- Manuscript Received: 29 NOV 2012
- NASA Cosmochemistry Fund. Grant Number: NNX12AH70G
High-precision Zn isotopic compositions measured by MC-ICP-MS are documented for 32 iron meteorites from various fractionally crystallized and silicate-bearing groups. The δ66Zn values range from −0.59‰ up to +5.61‰ with most samples being slightly enriched in the heavier isotopes compared with carbonaceous chondrites (0 < δ66Zn < 0.5). The δ66Zn versus δ68Zn plot of all samples defines a common linear fractionation line, which supports the hypothesis that Zn was derived from a single reservoir or from multiple reservoirs linked by mass-dependent fractionation processes. Our data for Redfields fall on a mass fractionation line and therefore refute a previous claim of it having an anomalous isotopic composition due to nonmixing of nucleosynthetic products. The negative correlation between δ66Zn and the Zn concentration of IAB and IIE is consistent with mass-dependent isotopic fractionation due to evaporation with preferential loss of lighter isotopes in the vapor phase. Data for the Zn concentrations and isotopic compositions of two IVA samples demonstrate that volatile depletion in the IVA parent body is not likely the result of evaporation. This is important evidence that favors the incomplete condensation origin for the volatile depletion of the IVA parent body.