New constraints on the 138La β-decay constant based on a geochronological study of granites from the Yilgarn Block, Western Australia

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doi: 10.1016/0009-2541(93)90158-F
Authors:Makishima, Akio; Nakamura, Eizo; Akimoto, Syun-iti; Campbell, Ian H.; Hill, Robert I.
Author Affiliations:Primary:
Okayama University, Institute for Study of the Earth's Interior, Misasa, Japan
Other:
Australian National University, Australia
Volume Title:Chemical Geology
Source:Chemical Geology, 104(1-4), p.293-300. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0009-2541
Publication Date:1993
Note:In English. 19 refs.; illus. incl. 2 tables
Summary:The β-decay constant of 138La has been geochronologically determined using Archean granites from the Yilgarn Block, Western Australia. Rb-Sr and Sm-Nd mineral isochron ages were obtained for the two granite samples, which are nearly identical with the ion microprobe U-Pb zircon ages. This agreement indicates that the closure date for these samples is the same, within analytical error, making them suitable for geochronological estimation of the β-decay constant for 138La. Applying a new method of Ce isotope analysis, with analytical reproducibility of ±0.008%, La-Ce isotope data for the studied samples resulted in precise mineral isochrons. Based on these internal mineral isochrons and ages determined by other geological clocks, the β-decay constant for 138La was estimated to be (2.33±0.24)·10-12a-1(2σ).
Subjects:Absolute age; Dates; Granites; Igneous rocks; Isochrons; Paleozoic; Plutonic rocks; Rb/Sr; Sm/Nd; Sr/Sr; Australasia; Australia; Western Australia; Yilgarn Craton; Ce/Ce; La/Ce
Abstract Numbers:93M/3824
Record ID:1993003475
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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