石酸盐显示自45.57亿年前以来的176Lu衰变率是恒定的
1Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada. yamelin@nrcan.gc.ca
概括
使用石酸盐矿物质确定精确的-176 (176Lu) 衰变常数值. 这解决了差异,并完善了地球演化研究的地质年代学.
科学领域:
- 地质化学 地质化学
- 太空化学 太空化学
- 射线测量约会的方法
背景情况:
- 准确的地质时代学对于理解地球演变至关重要.
- -176 (176Lu) 到 hafnium-176 (176Hf) 的放射性衰变系统对此至关重要.
- 之前的176Lu衰变常数测定显示了陆地和石数据之间的差异.
研究的目的:
- 为了精确确定176Lu的衰变常数.
- 为了调和从陆地矿物和石中获得的相互矛盾的值.
- 为了提高Lu-Hf地质年代学的准确性.
主要方法:
- 从酸盐矿物质中分析高放射性Lu-Hf数据.
- 使用来自理查德顿 (普通石) 和阿卡普尔科 (原始石) 石的酸盐矿物质.
- 与精确校准的- (U-Pb) 同位素系统进行比较.
主要成果:
- 从石中获得的新衰变常数值是1.864 x 10^-11 +/- 0.016 x 10^-11 年^-1 (理查顿) 和1.832 x 10^-11 +/- 0.029 x 10^-11 年^-1 (阿卡普尔科).
- 这些值在统计上与以前从陆地矿物中确定的值相同.
- 在石和陆地矿物数据之间实现了内部一致性.
结论:
- 176Lu衰变常数在地外 (石) 和地球样本之间是一致的.
- 这解决了之前的差异,并证实了对两者的Lu-Hf约会的使用.
- 地质时代学准确度的提高将改善地球和行星进化的模型.
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