利用钒同位素来确定月球形成物质的比例
Using Vanadium Isotopes to Constrain the Proportion of Lunar-forming Material
石震 1戚玉菡 2黄方 3丁昕1
作者信息
- 1. 中国科学院壳幔物质与环境重点实验室,中国科学技术大学地球和空间科学学院,合肥 230026
- 2. 中国科学院壳幔物质与环境重点实验室,中国科学技术大学地球和空间科学学院,合肥 230026;阿尔伯塔大学地球与大气科学系,加拿大埃德蒙顿阿尔伯塔,T6G 2E3
- 3. 中国科学院壳幔物质与环境重点实验室,中国科学技术大学地球和空间科学学院,合肥 230026;中国科学院比较行星学卓越创新中心,合肥 230026
- 折叠
摘要
经典碰撞模型是目前解释月球形成过程的最广为接受的假说,其要求一个约火星大小的撞击体Theia与吸积最后阶段的原始地球相撞,且月球主要来自撞击体Theia.然而关于撞击体对于月球质量贡献的百分比仍缺乏精确的制约.该研究采用地幔橄榄岩和科马提岩的高精度测量数据,用于重新评估硅酸盐全地球(BSE)的V同位素组成,相比之前的研究,新的数据表明δ51VBSE=-0.91‰±0.02‰(2SE,n=18).将其重新代入到地月双组分混合模型中,考虑了一个包含撞击前(原地球、Theia)和撞击后(地球、月球、逸出物质)成分的系统,得出现今月球中Theia的质量分数的最佳估计为MTheia=0.8*MMara时的73％到MThei=0.45*MEarth时的83％.这与先前的研究相比,降低了对Theia在月球形成中的贡献度约5％.这一结果为经典碰撞模型提供了更可靠的参数,有助于深化对月球形成过程的理解.
Abstract
The classic giant impact model is currently the most widely accepted hypothesis for explaining the lunar formation process.It posits a collision between a proto-Earth in its late accretion stage and a Mars-sized impactor named Theia.According to this model,the majority of the Moon's material is derived from Theia.However,there is still a lack of precise constraints on the contribution percentage of the impactor to the lunar mass.In this study,high-precision measurements of mantle peridotites and komatiites are employed to reevaluate the V isotope composition of the Bulk Silicate Earth(BSE).Unlike previous studies,the new data indicate δ51VBSE=-0.91±0.02‰(2SE,n=18).We incorporated this into a two-component mixing model for the Earth-Moon system,considering a system with pre-impact(proto-Earth,Theia)and post-impact(Earth,Moon,escaping mass)components.The best estimate for the mass fraction of Theia in the present Moon ranges from 73％for MTheia=0.8MMara to 83％for MTheia=0.45MEarth·This represents a reduction of approximately 5％in Theia's contribution compared to earlier studies.These findings provide more reliable parameters for the classic collision model,contributing to a deeper understanding of the lunar formation process.
关键词
经典碰撞模型/硅酸盐全地球/月球/钒同位素Key words
classical collision model/bulk silicate Earth/Moon/vanadium isotopes引用本文复制引用
基金项目
国家自然科学基金重点项目(41630206)
出版年
2024
国家科技期刊平台
NSTL
万方数据