Earth's volatile element depletion pattern inherited from a carbonaceous chondrite-like source

Area of Science:

• Planetary Science
• Geochemistry
• Cosmochemistry

Background:

• Earth's volatile element abundances are crucial for understanding planetary formation and habitability.
• The silicate Earth's composition shows similarities and differences with carbonaceous chondrites, early solar system materials.
• Core formation processes obscure volatile element depletion patterns in Earth's silicate portion.

Purpose of the Study:

• To investigate the volatile element depletion patterns in Earth and carbonaceous chondrites.
• To explain the apparent overabundance of indium in the silicate Earth.
• To refine estimates of volatile element abundances in Earth's core and bulk.

Main Methods:

• Analysis of high-precision sulfur, selenium, and tellurium data.
• Comparison of volatile element abundances between Earth and carbonaceous chondrites.
• Modeling of planetary accretion and core formation processes.

Main Results:

• Both Earth and carbonaceous chondrites display a 'hockey stick' volatile element depletion pattern.
• This pattern explains the indium overabundance in the silicate Earth without exotic explanations.
• The findings suggest accretion of 10-15% CI-like material before the cessation of core formation.

Conclusions:

• The 'hockey stick' pattern is a key characteristic of early solar system materials and Earth's building blocks.
• The study reconciles Earth's volatile element composition with carbonaceous chondrites.
• New constraints are provided for models of Earth's accretion and differentiation.