"Fe/Mg Ratio and Accretion"

 

Collisional erosion during the accretion of terrestrial planets significantly alters their chemical compositions. Specifically, the elevated Fe/Mg ratio of Earth's mantle could result from the preferential loss of silicate mantle during giant impacts. Using SPH simulations, the study quantifies mantle stripping under various impact conditions (velocity, angle, and mass ratios). These results inform an erosion model that predicts the accreted core, accreted mantle, and escaped mantle masses during impacts. When coupled with N-body simulations, the model reveals that 10% of the mantle is preferentially lost during accretion, aligning with Earth's superchondritic Fe/Mg ratio under both classical and Grand Tack accretion scenarios.

website: popularscientist.com

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