In-situ X-ray diffraction and radiography of iron-silicate-water-sulfur system simulating behaviors of light elements during early Earth's core-mantle segregation

The Earth's iron-rich core contains light elements. Studying the interaction of multiple light elements with iron and silicates during core-mantle segregation process in early Earth evolution has become important. In-situ X-ray diffraction and imaging observations of the iron-silicate-water-sulfur system at 5-10 GPa, up to approximately 1900 degrees C, were used to elucidate sequential reactions: phase transformation and hydrogenation of iron, and formation of iron sulfide and silicates. The newly constructed X-ray imaging system achieved spatial resolution of approx. 10 mu m for this study to show iron blob formation and motion. Sulfur distorted the iron blob shape and affected blob growth during heating by reducing the interfacial energy between molten iron and silicates. Light elements in the molten iron and the remaining silicate grains affected core-mantle segregation in the primitive Earth as temperatures increased. Carbon and silicon were incorporated into liquid Fe during later processes at higher temperatures.

Automated summary

The interaction of light elements with iron and silicates in Earth's core-mantle segregation process is crucial for understanding early Earth evolution. This study used in-situ X-ray diffraction and imaging observations to investigate the sequential reactions and formation of iron sulfide and silicates. The results showed that sulfur affected the shape and growth of iron blobs by reducing the interfacial energy between molten iron and silicates. Light elements and remaining silicate grains also played a role in core-mantle segregation as temperatures increased. Carbon and silicon were incorporated into liquid iron during later processes at higher temperatures.