Deep within the Earth, iron oxide withstands extreme temperatures and pressures

The core–mantle boundary (CMB) is the interface between the Earth's iron metal core and the thick rocky layer of mantle just above the core. It is a world of extremes—temperatures thousands of degrees Fahrenheit and pressures over a million times the pressure at the surface of the Earth. While it may seem far away from our environment on Earth's surface, plumes of material from the CMB can ascend upwards through the planet over tens of millions of years, influencing the chemistry, geologic structure, and plate tectonics of the surface world where we live.