Abstract
We report new nitrogen isotopic data in metals of H-, L- and one LL -chondrites, with N abundances in the range of ∼0.3 to 3.3 ppm and half of these ≤1 ppm. Nitrogen isotopic signatures in metals with low indigenous N concentrations are modified by cosmic ray spallation components; corrections are required to determine the indigenous N signatures. The metals of type 4 and 5 show uniform indigenous nitrogen (δ15N = -6.8 ± 0.5 ‰) and confirm a reported possible genetic association of chondritic metal with metal in IIE and IVA iron meteorites. Distinct isotopic signatures are observed in two metal samples of the Portales Valley (H6) meteorite which both are inconsistent with signatures in H4 and H5 chondrites, but possibly reveal a record of impact-induced melting and metamorphism on the parent asteroid. Anomalous nitrogen signatures in metals of type 3 chondrites, on the other hand, may reflect residues of surviving presolar isotopic signatures.
Original language | English |
---|---|
Pages (from-to) | 753-762 |
Number of pages | 10 |
Journal | Geochimica et Cosmochimica Acta |
Volume | 69 |
Issue number | 3 |
DOIs | |
State | Published - Feb 1 2005 |
Externally published | Yes |
Funding
We acknowledge A. Ruzicka and M. Kilgore for the Portales Valley samples. Helpful suggestions by S.V.S. Murty, R. Mohapatra, B. Marty, and an anonymous reviewer are appreciated. Work supported by NASA grant NAG5-12983.
Funders | Funder number |
---|---|
National Aeronautics and Space Administration | NAG5-12983 |