气候变化领域集成服务门户(CCPortal): Cosmic ray effects on the isotope composition of hydrogen and noble gases in lunar samples: Insights from Apollo 12018

CCPortal

DOI	10.1016/j.epsl.2020.116550
	Cosmic ray effects on the isotope composition of hydrogen and noble gases in lunar samples: Insights from Apollo 12018
	Füri E.; Zimmermann L.; Deloule E.; Trappitsch R.
发表日期	2020
ISSN	0012821X
卷号	550
英文摘要	Exposure of rocks and regolith to solar (SCR) and galactic cosmic rays (GCR) at the Moon's surface results in the production of ‘cosmogenic’ deuterium and noble gas nuclides at a rate that depends on a complex set of parameters, such as the energy spectrum and intensity of the cosmic ray flux, the chemical composition, size, and shape of the target as well as the shielding depth. As the effects of cosmic rays on the D production in lunar samples remain poorly understood, we determine here the D content and noble gas (He-Ne-Ar) characteristics of nominally anhydrous mineral (olivine and pyroxene) grains and rock fragments, respectively, from different documented depths (0 to ≥4.8 cm) within Apollo olivine basalt 12018. Deuterium concentrations, determined by secondary ion mass spectrometry, and cosmogenic 3He, 21Ne, and 38Ar abundances, measured by CO2 laser extraction static mass spectrometry, are constant over the depth range investigated. Neon isotope ratios (20Ne/22Ne ≈0.86 and 21Ne/22Ne ≈0.85) of the cosmogenic endmember are comparable to the theoretical signature of GCR-produced neon. These observations indicate that the presence of significant amounts of SCR nuclides in the studied sub-samples can be ruled out. Hence, D within the olivines and pyroxenes must have been predominantly produced in situ by GCR-induced spallation reactions during exposure at the lunar surface. Comparison of the amount of D with the 21Ne (184 ± 26 Ma) or 38Ar (193 ± 25 Ma) exposure ages yields a D production rate that is in good agreement with the value of (2.17±0.11)×10−12 mol(g rock)−1Ma−1 from Füri et al. (2017). These results confirm that cosmic ray effects can substantially alter the hydrogen isotope (D/H) ratio of indigenous ‘water’ in returned extraterrestrial samples and meteorites with long exposure ages. © 2020 The Author(s)
关键词	cosmic rays cosmogenic nuclides exposure age hydrogen isotopes mare basalt noble gases
英文关键词	Carbon dioxide lasers; Cosmic rays; Deuterium; Hydrogen; Mineral industry; Moon; Neon; Olivine; Secondary ion mass spectrometry; Chemical compositions; Galactic cosmic rays; Hydrogen isotope; Isotope compositions; Nominally anhydrous minerals; Olivine basalts; Production rates; Spallation reactions; Cosmology; comparative study; concentration (composition); cosmic ray; hydrogen isotope; isotopic composition; lunar soil; Moon; noble gas; reaction kinetics; rock
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202588
作者单位	Centre de Recherches Pétrographiques et Géochimiques, Université de Lorraine, CNRS, Nancy, F-54000, France; Lawrence Livermore National Laboratory, Nuclear and Chemical Sciences Division, 7000 East Ave, L-231, Livermore, CA 94550, United States
推荐引用方式 GB/T 7714	Füri E.,Zimmermann L.,Deloule E.,et al. Cosmic ray effects on the isotope composition of hydrogen and noble gases in lunar samples: Insights from Apollo 12018[J],2020,550.
APA	Füri E.,Zimmermann L.,Deloule E.,&Trappitsch R..(2020).Cosmic ray effects on the isotope composition of hydrogen and noble gases in lunar samples: Insights from Apollo 12018.Earth and Planetary Science Letters,550.
MLA	Füri E.,et al."Cosmic ray effects on the isotope composition of hydrogen and noble gases in lunar samples: Insights from Apollo 12018".Earth and Planetary Science Letters 550(2020).