The innermost part of the Earth consisting of a solid → inner core,
mainly composed of → iron, and a → liquid → outer core.
The → pressure and → temperature
are so extreme that the molten iron solidifies.
The temperature at the inner core boundary is expected to be close to the
→ melting point of iron at 330 gigapascal (GPa).
From static laser-heated diamond anvil cell experiments up to 200 GPa, using
synchrotron-based fast → X-ray diffraction as a primary melting
diagnostic, S. Anzellini et al. (2013, Science 340, 484)
conclude that the melting temperature of iron at the inner core boundary is
6230 ± 500 K. This estimation favors a high heat flux at the core-mantle
boundary with a possible partial melting of the → mantle.
The inner core, 2,400 km in diameter, is suspended in the molten metal of the
→ outer core, which is about 2,240 km thick.
The temperature difference between the mantle and the core is the main engine for
large-scale thermal movements, which coupled with the
→ Earth’s rotation, function
as a generator for the planet’s → magnetic field.
See also: → Earth; → core.
