Alpha-decay of 184Os revealed by radiogenic 180W in meteorites: Half life determination and viability as geochronometer
Alpha-decay of 184Os revealed by radiogenic 180W in meteorites: Half life determination and viability as geochronometer
复制标题
陨石中放射源 180W 揭示了 184Os 的 α 衰变：半衰期测定和作为地质计时器的可行性
DOI：
10.1016/j.epsl.2014.01.030
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发表时间：
2014
影响因子：
5.3
通讯作者：
Schulz
中科院分区：
文献类型：
--
作者：
Peters;Münker;Becker;Schulz
The decay of the rare nuclide 184 Os by alpha emission to 180 W has been theoretically predicted, but was previously never observed in experiments. Variable excesses of 180 W were recently observed for iron meteorites, but the contribution to these excesses by 184 Os-decay was regarded as insignificant. Here, we present combined 180 W and Os–W concentration data for meteorites and terrestrial rocks, now indicating that the 180 W heterogeneities can be explained by α-decay of 184 Os. A combined 184 Os–180 W isochron for iron meteorites and chondrites yields a decay constant value of λ 184 Os (α) of 6.49±1.34× 10− 14 a− 1 (half life 1.12±0.23× 10 13 yr), in good agreement with theoretical estimates. The 184 Os–180 W decay system may constitute a viable tracer and chronometer for important geological processes like core formation, silicate differentiation or late accretion processes. This is illustrated by a measured 180 W-deficit in terrestrial basalts relative to chondrites by 1.16±0.69 parts in 10 000, consistent with core formation∼ 4.5 Ga ago.
