A Relic of Ancient Oceans and Planetary Collisions

New research suggest the mysterious D” layer at Earth’s core-mantle boundary might have formed from remnants of an early colossal impact, with iron-rich peroxide playing a key role in its unique and enduring features.

Deep within Earth, there lies a mysterious layer called the D” layer. Located roughly 3,000 kilometers down, this zone sits just above the boundary between the planet’s molten outer core and its solid mantle. Unlike a perfect sphere, the D” layer is surprisingly patchy. Its thickness varies greatly from place to place, with some regions even lacking a D” layer altogether – much like continents rise above the Earth’s oceans. These intriguing variations have captured the attention of geophysicists, who describe the D” layer as a heterogeneous, or non-uniform, region.