Geochemical models of core-mantle differentiation

The core-mantle differentiation process is one of the most significant events in the Earth's early history, which profoundly affects the Earth's internal structure. According to the simple core-mantle differentiation mechanism, elements such as iron and nickel should be extracted from silicate to form an iron-rich proto-core, and the residual silicate materials form the proto-mantle. However, the composition of the lower mantle and the core remains controversial, which largely affects the partition of elements, thus the referred differentiation process of the Earth. In recent years, many experimental studies on the partition coefficient of siderophile elements between metal and silicate under high-temperature and high-pressure conditions have put forward new ideas on the issues around Earth's core-mantle differentiation. Meanwhile, some researchers suggested that the redox state of the Earth's mantle changes during its formation and evolution, and many isotope geochemistry studies support that some enstatite chondrites have a common nebular precursor as the Earth. These new studies bring dispute on the Earth's building materials, which dominates the core-mantle differentiation process and largely affects the partitioning behaviors of elements during the core-mantle differentiation. This chapter aims to review recent experimental studies on the siderophile element geochemistry and discussions on the Earth's building blocks.