Welcome to Geological Journal of China Universities ! Today is
Share:

Geological Journal of China Universities ›› 2024, Vol. 30 ›› Issue (03): 371-378.DOI: 10.16108/j.issn1006-7493.2023065

Previous Articles    

Using Vanadium Isotopes to Constrain the Proportion of Lunar-forming Material

SHI Zhen1,QI Yuhan1,2,HUANG Fang1,3,DING Xin1*   

  1. 1. CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences; University of Science and Technology of China, Hefei 230026, China;
    2. Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada;
    3. CAS Center for Excellence in Comparative Planetology, Hefei 230026, China
  • Online:2024-07-03 Published:2024-07-03

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=0.8MMars 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.

Key words: classical collision model, bulk silicate Earth, Moon, vanadium isotopes

CLC Number: