Melting and adiabatic temperature distributions in the outer earth core

Abstract

The Ross-Lindemann melting criterion is employed to derive a theoretical melting curve for iron in the pressure range of the outer core of the Earth. The intermolecular potential used is a rydberg function. The agreement with the available experimental data is guaranteed fairly well. The melting point of iron at the mantle-core boundary results to be 3950 K, and 5650 K at the outer-core-inner-core, boundary with an average gradient of about 0.76 deg/km in the outer core. Taking into account recent results on the thermodynamical Gruneisen gamma, the adiabatic temperature distribution through the outer core is also given. No overlapping of the two curves is found which leaves open the possibility of explaining the thermodynamics of the core and the origin of the geomagnetic field in the classical way, by definitely avoiding the so-called core paradox.