A Caltech Library Service

^(87)Rb-^(87)Sr isochron and ^(40)K-^(40)Ar ages of the norton county achondrite

Bogard, D. D. and Burnett, D. S. and Eberhardt, P. and Wasserburg, G. J. (1967) ^(87)Rb-^(87)Sr isochron and ^(40)K-^(40)Ar ages of the norton county achondrite. Earth and Planetary Science Letters, 3 . pp. 179-189. ISSN 0012-821X.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


Analysis of seven different portions of Norton County yielded Rb/Sr ratios ranging from 0.15 to 2.3 and permitted the determination of an isochron with high precision. The Rb and Sr concentrations were found to be as low as ∼0.16 ppm. All of the data lie to within their experimental errors on a line in the Sr evolution diagram of slope 0.0654 ± 0.0014, and intercept 0.700 ± 0.002. This determines an age of 4.7 ± 0.1 × 10^9 yr for λ = 1.39 × 10^(−11) yr^(−1). ^(40)K^(40)Ar ages on samples containing 42, 53 and 107 ppm K gave ages of 4.2 – 4.5 × 10^9 yr which are compatible with the Rb-Sr age. The K appears to be concentrated in alkali feldspar grains of about 5–50 microns. The ^(87)Rb^(87)Sr age and primary ^(87)Sr/^(86)Sr value is of sufficient precision to permit the age resolution of meteoritic objects which were formed 0.3 × 10^9 yr apart. No evidence of element redistribution was found for Norton Country as indicated by the consistency of our Rb-Sr and K-Ar results.

Item Type:Article
Related URLs:
URLURL TypeDescription
Burnett, D. S.0000-0001-9521-8675
Wasserburg, G. J.0000-0002-7957-8029
Additional Information:© 1967 Elsevier B.V. Received 14 November 1967. This paper is dedicated to Professor H. H. Nininger for his pioneer efforts in finding and collecting meteorites and making them available for scientific research. The samples used in this research were obtained from the Nininger Meteorite Collection at the Arizona State University through the aid of C. W. Moore. An additional sample of the Norton County Meteorite to was provided by W. Nichiporok. We gratefully acknowledge the assistance of T. Wen in the chemical an J mass spectrometric analyses. The electron microprobe data were obtained with the help of A. E. Bence and A. Chodos. This research was supported by grants from the National Science Foundation, NSF GA-464 and NSF GP-5391 and the U.S. Atomic Energy Commission AEC (AT-04-3(427)).
Funding AgencyGrant Number
Atomic Energy Commission (AEC)AT-04-3(427)
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological Sciences1497
Record Number:CaltechAUTHORS:20130220-104628650
Persistent URL:
Official Citation:D.D. Bogard, D.S. Burnett, P. Eberhardt, G.J. Wasserburg, ^(87)Rb^(87)Sr isochron and ^(40)K^(40)Ar ages of the norton county achondrite, Earth and Planetary Science Letters, Volume 3, 1967–1968, Pages 179-189, ISSN 0012-821X, 10.1016/0012-821X(67)90033-7. (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37016
Deposited By: Ruth Sustaita
Deposited On:20 Feb 2013 19:17
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page