AI Article Synopsis
- A unique xenolith discovered in the metal-rich chondrite Isheyevo has a pristine mineral makeup similar to interplanetary dust particles (IDPs), but is much larger—over 30,000 times the volume of a typical IDP.
- This xenolith exhibits a wide range of nitrogen isotopic variation, from very light compositions akin to those of the solar nebula to the heaviest ratios found in solar system materials.
- The hydrogen and carbon isotopic compositions of the xenolith show little variation, challenging current models that explain the origins of light element isotopic anomalies.
Article Abstract
Pristine meteoritic materials carry light element isotopic fractionations that constrain physiochemical conditions during solar system formation. Here we report the discovery of a unique xenolith in the metal-rich chondrite Isheyevo. Its fine-grained, highly pristine mineralogy has similarity with interplanetary dust particles (IDPs), but the volume of the xenolith is more than 30,000 times that of a typical IDP. Furthermore, an extreme continuum of N isotopic variation is present in this xenolith: from very light N isotopic composition (delta(15)N(AIR) = -310 +/- 20 per thousand), similar to that inferred for the solar nebula, to the heaviest ratios measured in any solar system material (delta(15)N(AIR) = 4,900 +/- 300 per thousand). At the same time, its hydrogen and carbon isotopic compositions exhibit very little variation. This object poses serious challenges for existing models for the origin of light element isotopic anomalies.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2705565 | PMC |
| http://dx.doi.org/10.1073/pnas.0901546106 | DOI Listing |
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