Girault Frédéric, Ferrière Ludovic, Sadaka Carine, Chacartegui Rojo Íñigo de Loyola, Losno Rémi, Moynier Frédéric, Perrier Frédéric, Meslin Pierre-Yves
Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, F-75005, Paris, France.
Natural History Museum Vienna, Burgring 7, A-1010, Vienna, Austria.
Sci Rep. 2025 Jan 28;15(1):3517. doi: 10.1038/s41598-025-86842-x.
The radioactive gas radon-222, a fluid and aerosol tracer in Earth's lithosphere and atmosphere, can also reveal subtle rock physics processes in extraterrestrial environments, such as those involving water, but remains poorly constrained in planetary bodies due to the limited number of samples available. Here we measure the effective radium-226 concentration (EC) of six Martian and nine lunar meteorites to derive radon source terms for Martian and lunar rocks. EC values are 0.029-0.78 and 0.045-0.80 Bq kg for Martian and lunar meteorites, respectively (0.041 ± 0.003 Bq kg for falls and 0.28 ± 0.02 Bq kg for finds), lower than most terrestrial rocks but similar to other meteorites and terrestrial primitive basalts. The effect of terrestrial alteration on EC and its temperature sensitivity are also determined experimentally. Radon emanation coefficient values are 2.1-17% (mean: 8.1 ± 2.5%) for Martian meteorites and 0.43-11% (mean: 5.5 ± 1.0%) for lunar meteorites. Mean estimated surface radon fluxes for Mars and the Moon are 0.16-0.60 and 0.33-0.44 mBq m s (78-280 and 160-210 atoms m s), respectively, much lower than on Earth (21 mBq m s or 10 atoms m s). Our meteorite analyses constrain radon emanation on Mars and the Moon and provide a basis for current and future in-situ measurements.
放射性气体氡 - 222是地球岩石圈和大气中的一种流体和气溶胶示踪剂，它也能揭示外星环境中微妙的岩石物理过程，比如那些涉及水的过程，但由于可用样本数量有限，在行星体中的情况仍知之甚少。在此，我们测量了六块火星陨石和九块月球陨石的有效镭 - 226浓度（EC），以得出火星和月球岩石的氡源项。火星陨石和月球陨石的EC值分别为0.029 - 0.78和0.045 - 0.80贝克勒尔每千克（降落陨石为0.041 ± 0.003贝克勒尔每千克，发现陨石为0.28 ± 0.02贝克勒尔每千克），低于大多数地球岩石，但与其他陨石和地球原始玄武岩相似。还通过实验确定了地球蚀变对EC的影响及其温度敏感性。火星陨石的氡析出系数值为2.1% - 17%（平均值：8.1 ± 2.5%），月球陨石的氡析出系数值为0.43% - 11%（平均值：5.5 ± 1.0%）。火星和月球的平均估计表面氡通量分别为0.16 - 0.60和0.33 - 0.44毫贝克勒尔每平方米每秒（78 - 280和160 - 210个原子每平方米每秒），远低于地球（21毫贝克勒尔每平方米每秒或10个原子每平方米每秒）。我们对陨石的分析限制了火星和月球上的氡析出，并为当前和未来的原位测量提供了基础。
