Primordial origins of Earth's carbon

TL;DR

This paper reviews the astrophysical origins of Earth's carbon, from Big Bang products to Earth's formation, including primitive object compositions, planetary formation models, and Earth's carbon reservoirs.

Contribution

It provides a comprehensive synthesis of current knowledge on Earth's carbon origins, integrating astrophysical, geochemical, and planetary formation perspectives.

Findings

Primitive objects contain diverse carbon compositions.

Volatile delivery to Earth involves multiple sources.

Earth's carbon reservoirs are complex and not fully understood.

Abstract

In this chapter we review the astrophysical origins of Earth's carbon, starting from the products of the Big Bang and culminating with the Earth's formation. We review the measured compositions of different primitive objects including comets, various classes of meteorites and interstellar dust particles. We discuss the composition of the Solar Nebula, especially with regards to the distribution of volatiles such as carbon. We discuss dynamical models of planetary formation from planetesimals and planetary embryos, and the timescale for volatile delivery to the growing Earth from different sources. Finally, we review Earth's carbon reservoirs. Throughout the chapter we highlight open questions related to planet formation, meteoritics, and geochemistry.