A new study led by Rutgers geodynamicist Yoshinori Miyazaki offers a compelling explanation for some of the most enigmatic structures hidden deep within Earth and connects them directly to the planet’s molten beginnings and long-term habitability. For decades, scientists have been puzzled by two massive anomalies located nearly 1,800 miles beneath the surface at the boundary between Earth’s mantle and core. Their size, composition, and behavior do not fit neatly into traditional models of planetary formation, suggesting that key pieces of Earth’s early history were missing from existing theories.
The study, published in Nature Geoscience, focuses on large low-shear-velocity provinces, enormous regions of unusually hot and dense rock located beneath Africa and the Pacific Ocean, as well as smaller features known as ultra-low-velocity zones. These structures significantly slow seismic waves, indicating that their chemical composition differs from that of the surrounding mantle. Rather than being random irregularities, the researchers argue that these formations are ancient remnants of Earth’s earliest evolutionary stages.
According to Miyazaki, Earth was once covered by a global magma ocean shortly after its formation. As this molten planet cooled, scientists long expected the mantle to solidify into distinct chemical layers, similar to how liquids separate by density when frozen. However, seismic observations reveal that such orderly layering never developed. Instead, material accumulated unevenly near the bottom of the mantle, forming large low-shear-velocity provinces and ultra-low-velocity zones in clustered, irregular patterns. This contradiction between theory and observation prompted the researchers to re-examine the role of Earth’s core in shaping the mantle.
Using geodynamic modeling combined with mineral physics and seismic data, the team identified the missing factor: chemical exchange between the core and mantle. Their model suggests that over billions of years, elements such as silicon and magnesium slowly leaked from the core into the overlying mantle. This process disrupted chemical layering and helped preserve regions of anomalous composition near the core–mantle boundary. The researchers interpret large low-shear-velocity provinces as solidified remnants of a “basal magma ocean” that became chemically contaminated by core material during Earth’s early evolution.
These findings have implications that extend far beyond deep-Earth chemistry. Core–mantle interactions may have influenced how Earth cooled, how mantle convection developed, and how volcanic activity has been sustained over geological time. The anomalous structures may even feed mantle plumes that power surface hotspots such as Hawaii and Iceland, directly linking Earth’s deepest interior to its surface geology. More broadly, these processes may have shaped atmospheric evolution, helping explain why Earth retained water and life while Venus became a runaway greenhouse world and Mars lost most of its atmosphere.
By reframing large low-shear-velocity provinces as chemical fingerprints of early core–mantle interaction, the study provides a new narrative for Earth’s evolution. It suggests that Earth’s interior still carries a memory of its molten origins, and that this deep internal history played a crucial role in making the planet uniquely habitable.