Experimental Modeling of the Process of Formation of Native Metals (Fe) in the Earth's Crust in the Restorative Conditions

The work presents the results of the experimental modeling of the process of formation of native Fe in the earth's crust when the basalt melts interacting with fluid (H₂, H₂+CH₄) at temperatures (1100-1250°C), fluid pressure (1-100 MPa) in strongly restored conditions - fO₂ = 10-12-10-14 bar. The experiments were carried out using the installation of a high gas pressure equipped with a unique device that provides long-term experiments at high temperatures and fluid pressure. In the experiments, natural samples of magmatic rocks were used: the magnesian basalt of the northern breakthrough of the volcano Tolbachik (Kamchatka), as well as a magnesian basalt, enriched with nickel and cobalt oxides. Based on the experimental modeling, the following features of the process of interaction between the recovery fluid with basalt melts are established: 1. Despite the high restoration potential of the H₂ system or the mixture (H₂+CH₄) - a magmatic melt, hydrogen oxidation reactions and the complete restoration of metals oxides in the melting do not go to the end. The cessation of redox reactions in the basalt melt occurs due to the formation of H₂O in the melt, buffering the restoration potential of hydrogen or mixture (H₂+CH₄). 2. Initially, the homogeneous magmatic melt becomes heterogeneous: the formed H₂O dissolves in the melt and, partially, in the fluid phase, while melts of more sour composition and small metal isolations of the liquidation structure are formed. 3. The process of metal-silicate liquidation in magmatic melts in their interaction with a restorative fluid can be carried out at real temperatures of the magmas in nature (≤1250°C), significantly lower corresponding melting temperatures of iron and its alloys with nickel and cobalt. 4. Carbon, which is formed in experiments due to pyrolysis CH₄, dissolves in the metal phase. Thus, the mechanism responsible for the presence of carbon in a native basalt in nature is experimentally substantiated. 5. The structure and sizes of experimentally installed metal isolations are well consistent with natural data on finds of native metals, primarily iron and its alloys with nickel and cobalt, in magmatic rocks of various composition and genesis.