NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Al-26-Mg-26 ages of iron meteoritesAn exposure age for an iron meteorite can be calculated from measurements of a radioactive nuclide and a stable nuclide that are produced by similar sets of nuclear reactions, provided that the stable nuclide is present with low initial abundance. The standard methods rely on either K-40 (t(sub 1/2) = 1.26 Gy), K-39, and K-41 or on a shorter-lived radionuclide and a stable, noble gas isotope. Widely used pairs of this type include Cl-36/Ar-36 and Al-26/Ne-21. Other pairs that may serve the purpose for iron meteorites contain many stable isotopes besides those of K and the noble gases that are produced partly by cosmic rays. We consider here the calculation of exposure ages, t(sub 26), from measurements of Al-26 (t(sub 1/2) = 0.7 My) and (stable) Mg-26. Ages based on Al-26/Mg-26 ratios, like those based on Cl-36/Ar-36 ratios, are 'buffered' against changes in relative production rates due to shielding because decay of the radioactive nuclide accounts for a good part of the inventory of the stable nuclide.
Document ID
19940011767
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Herzog, G. F.
(Rutgers Univ. New Brunswick, NJ, United States)
Souzis, A. E.
(Army Research Lab. Fort Belvoir, VA., United States)
Xue, S.
(Rutgers Univ. New Brunswick, NJ, United States)
Klein, J.
(Pennsylvania Univ. Philadelphia., United States)
Juenemann, D.
(Pennsylvania Univ. Philadelphia., United States)
Middleton, R.
(Pennsylvania Univ. Philadelphia., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Lunar and Planetary Inst., Twenty-Fourth Lunar and Planetary Science Conference. Part 2: G-M
Subject Category
Astrophysics
Accession Number
94N16240
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available