Details
| Original language | English |
|---|---|
| Pages (from-to) | 449-451 |
| Number of pages | 3 |
| Journal | SCIENCE |
| Volume | 327 |
| Issue number | 5964 |
| Publication status | Published - 22 Jan 2010 |
| Externally published | Yes |
Abstract
The 238U/235U isotope ratio has long been considered invariant in meteoritic materials (equal to 137.88). This assumption is a cornerstone of the high-precision lead-lead dates that define the absolute age of the solar system. Calcium-aluminum-rich inclusions (CAls) of the Allende meteorite display variable 238U/235U ratios, ranging between 137.409 ± 0.039 and 137.885 ± 0.009. This range implies substantial uncertainties in the ages that were previously determined by lead-lead dating of CAls, which may be overestimated by several million years. The correlation of uranium isotope ratios with proxies for curium/uranium (that is, thorium/uranium and neodymium/uranium) provides strong evidence that the observed variations of 238U/235U in CAls were produced by the decay of extant curium-247 to uranium-235 in the early solar system, with an initial 247Cm/235U ratio of approximately 1.1 × 10-4 to 2.4 × 10-4.
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In: SCIENCE, Vol. 327, No. 5964, 22.01.2010, p. 449-451.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - 238U/235U variations in meteorites
T2 - Extant 247Cm and implications for Pb-Pb dating
AU - Brennecka, G. A.
AU - Weyer, S.
AU - Wadhwa, M.
AU - Janney, P. E.
AU - Zipfel, J.
AU - Anbar, A. D.
PY - 2010/1/22
Y1 - 2010/1/22
N2 - The 238U/235U isotope ratio has long been considered invariant in meteoritic materials (equal to 137.88). This assumption is a cornerstone of the high-precision lead-lead dates that define the absolute age of the solar system. Calcium-aluminum-rich inclusions (CAls) of the Allende meteorite display variable 238U/235U ratios, ranging between 137.409 ± 0.039 and 137.885 ± 0.009. This range implies substantial uncertainties in the ages that were previously determined by lead-lead dating of CAls, which may be overestimated by several million years. The correlation of uranium isotope ratios with proxies for curium/uranium (that is, thorium/uranium and neodymium/uranium) provides strong evidence that the observed variations of 238U/235U in CAls were produced by the decay of extant curium-247 to uranium-235 in the early solar system, with an initial 247Cm/235U ratio of approximately 1.1 × 10-4 to 2.4 × 10-4.
AB - The 238U/235U isotope ratio has long been considered invariant in meteoritic materials (equal to 137.88). This assumption is a cornerstone of the high-precision lead-lead dates that define the absolute age of the solar system. Calcium-aluminum-rich inclusions (CAls) of the Allende meteorite display variable 238U/235U ratios, ranging between 137.409 ± 0.039 and 137.885 ± 0.009. This range implies substantial uncertainties in the ages that were previously determined by lead-lead dating of CAls, which may be overestimated by several million years. The correlation of uranium isotope ratios with proxies for curium/uranium (that is, thorium/uranium and neodymium/uranium) provides strong evidence that the observed variations of 238U/235U in CAls were produced by the decay of extant curium-247 to uranium-235 in the early solar system, with an initial 247Cm/235U ratio of approximately 1.1 × 10-4 to 2.4 × 10-4.
UR - http://www.scopus.com/inward/record.url?scp=75749153628&partnerID=8YFLogxK
U2 - 10.1126/science.1180871
DO - 10.1126/science.1180871
M3 - Article
AN - SCOPUS:75749153628
VL - 327
SP - 449
EP - 451
JO - SCIENCE
JF - SCIENCE
SN - 0036-8075
IS - 5964
ER -