TY - JOUR
T1 - 138La β-decay constant estimated from geochronological studies
AU - Masuda, A.
AU - Shimizu, H.
AU - Nakai, S.
AU - Makishima, A.
AU - Lahti, S.
N1 - Funding Information:
We thank Professor H. Baadsgaard (University of Alberta) for donation of samples, Professor D. Bridgwater (Copenhagen University) and O. Kouvo (Geological Survey of Finland) for helpful information and Dr. T. Tanaka (Geological Survey of Japan) for helpful discussion. Permission to publish results on material from the Geological Survey of Greenland (GGUl10999) is acknowledged. This research was supported by grant-in-aid for Scientific Research from Ministry of Education, Science and Culture of Japan.
PY - 1988/8
Y1 - 1988/8
N2 - LaCe ages are reported for two sets of Finnish pegmatites, Lövböle and Mustikkamäki, and for an Amîtsoq gneiss, Greenland. When λβ 138La value (2.29 × 10-12 yr-1) obtained by radioactivity measurement [1] is used for the chronological calculation, the LaCe ages (2129, 2325, 3271 Myr) evaluated for these rocks are 18-35% older than the SmNd ages for the same samples. To make the LaCe age fit to the SmNd age for the same sample, a new value of (2.77 ± 0.21) × 10-12 yr-1 is evaluated for λβ 138La. In this calculation, the LaCe and SmNd ages reported for a Bushveld gabbro [2] have been also taken into account together with those for the Lövböle pegmatite and the Mustikkamäki pegmatite, while the Amîtsoq gneiss (GGU110999) has been omitted because of the complicated thermal history of this sample.
AB - LaCe ages are reported for two sets of Finnish pegmatites, Lövböle and Mustikkamäki, and for an Amîtsoq gneiss, Greenland. When λβ 138La value (2.29 × 10-12 yr-1) obtained by radioactivity measurement [1] is used for the chronological calculation, the LaCe ages (2129, 2325, 3271 Myr) evaluated for these rocks are 18-35% older than the SmNd ages for the same samples. To make the LaCe age fit to the SmNd age for the same sample, a new value of (2.77 ± 0.21) × 10-12 yr-1 is evaluated for λβ 138La. In this calculation, the LaCe and SmNd ages reported for a Bushveld gabbro [2] have been also taken into account together with those for the Lövböle pegmatite and the Mustikkamäki pegmatite, while the Amîtsoq gneiss (GGU110999) has been omitted because of the complicated thermal history of this sample.
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U2 - 10.1016/0012-821X(88)90119-7
DO - 10.1016/0012-821X(88)90119-7
M3 - Article
AN - SCOPUS:0024224351
SN - 0012-821X
VL - 89
SP - 316
EP - 322
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 3-4
ER -