Geochemistry

Tectonics

Mantle (geology)

Plate tectonics

Geodynamics

Early Earth

Archean

Hadean

Earth science

Craton

Geology

Paleontology

Crust

Proceedings of the National Academy of Sciences

SignificanceDue to active plate tectonics, there are no direct rock archives covering the first ca. 500 million y of Earth's history. Therefore, insights into Hadean geodynamics rely on indirect observations from geochemistry. We present a high-precision 182W dataset for rocks from the Kaapvaal Craton, southern Africa, revealing the presence of Hadean protocrustal remnants in Earth's mantle. This has broad implications for geochemists, geophysicists, and modelers, as it bridges contrasting 182W isotope patterns in Archean and modern mantle-derived rocks. The data reveal the origin of seismically and isotopically anomalous domains in the deep mantle and also provide firm evidence for the operation of silicate differentiation processes during the first 60 million y of Earth's history.

Long-term preservation of Hadean protocrust in Earth’s mantle