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Comparative U-Th-Pb systematics in 2.7 × 10⁹yr plutons of different geologic histories

Steiger, R. H. and Wasserburg, G. J. (1969) Comparative U-Th-Pb systematics in 2.7 × 10⁹yr plutons of different geologic histories. Geochimica et Cosmochimica Acta, 33 (10). pp. 1213-1232. ISSN 0016-7037. doi:10.1016/0016-7037(69)90043-x.

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A comparative study was made of the Pb-U-Th systematics on cogenetic zircons from three plutons with different geological histories but the same age (2.69 × 10⁹ yr). The first of these is in the Superior Province, Canada and is believed to be a virginal body. Assuming an episodic model, a secondary age of 455 ±³⁰⁵₁₀₅m.y. is inferred. The second body is from the Grenville front and is known to have suffered an episode at 920 m.y. However, a secondary age of 350 ± 50 m.y. is inferred. A third body in the Wind River Mountains, Wyoming, has no known metamorphic history, but was uparched in Laramide time. After Naylor et al. (1968) a secondary age of 130 ±⁸⁰₁₀₀m.y. is inferred, We conclude that unless independently documented, the secondary ages inferred by the episodic model are in general invalid. The zircon systematics appear to be dominated by the occurrence of highly discordant and almost concordant phases. The discordant phase responding to diffusion loss which may be in the “non linear” region.

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Wasserburg, G. J.0000-0002-7957-8029
Additional Information:© 1969 Published by Elsevier Ltd. Received 31 January 1969; accepted in revised form 29 May 1969. The authors wish to thank R. S. NAYLOR for his interest in this study and his willingness to engage in serious discussion of this problem. The analytical work was carried out with the able assistance of Mr. THEODORE WEN, and Mrs. MARIA SANTILLANA and the careful mineral separations by Mr. J. BROWN. This work was supported by the National Science Foundation (Grants GP-7976, GA-1073) and in part by a contract with the Atomic Energy Commission (AT(04-3)-427).
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Atomic Energy CommissionAT(04-3)-427
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Caltech Division of Geological Sciences1610
Issue or Number:10
Record Number:CaltechAUTHORS:20220616-446264100
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Official Citation:R.H Steiger, G.J Wasserburg, Comparative U-Th-Pb systematics in 2.7 × 109yr plutons of different geologic histories, Geochimica et Cosmochimica Acta, Volume 33, Issue 10, 1969, Pages 1213-1232, ISSN 0016-7037, (
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ID Code:115187
Deposited By: Tony Diaz
Deposited On:21 Jun 2022 19:26
Last Modified:21 Jun 2022 19:26

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