Computer Science
Scientific paper
Oct 1976
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1976e%26psl..32..191m&link_type=abstract
Earth and Planetary Science Letters, vol. 32, no. 2, Oct. 1976, p. 191-198.
Computer Science
6
Meteoritic Composition, Norton County Achondrite, Radioactive Age Determination, Rubidium Isotopes, Strontium Isotopes, Abundance, Crystal Structure, Enstatite, Least Squares Method, Olivine, Polycrystals, Time Dependence
Scientific paper
Results are presented for Rb-87 - Sr-87 analysis of nine samples from the Norton County achondrite, which consists essentially of large enstatite crystals in a mass of fine-grained polycrystalline enstatite and olivine with small flecks of metallic phases. Blank corrections were applied to each analysis because of the low Rb and Sr concentrations in the samples. It is shown that the concentrations of K, Rb, and Sr are low and vary strongly between the enstatite crystals and the matrix; the differences are attributed to the presence of oligoclase in the matrix. The feldspar component is found to contain 70 per cent of the Sr and 30 per cent of the Rb in the meteorite. A least-squares treatment of the feldspar and whole-rock data gives an age of about 4.68 billion years and an initial Sr-87/Sr-86 ratio of approximately 0.6985, while the secondary isochron gives an age of about 4.48 billion years and an initial ratio of approximately 0.7005. It is proposed that this meteorite formed about 4.6 billion years ago with an initial Sr-87/Sr-86 ratio similar to Allende's and that impact-induced metamorphism occurred about 120 million years later, resulting in incomplete isotopic reequilibration.
Allègre Claude J.
Minster Jean-François
No associations
LandOfFree
Rb-87 - Sr-87 history of the Norton County enstatite achondrite does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Rb-87 - Sr-87 history of the Norton County enstatite achondrite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rb-87 - Sr-87 history of the Norton County enstatite achondrite will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1568687