Possibility of the natural electric field formation in conditions of the lateritic weathering crust of the ultra basic rocks in presence of extended in depth magnetite bearing bodies is proved. Theoretical curves of concentration of the dissolved oxygen and oxidized forms of magnetite are obtained. It is enough satisfied coincidence with the experimental data.
Tectonic fractures of meridian spread, masked by block system of neotectonic breaks, play the leading role in structural control of nickel mineralization in supergene nickel deposits in the Urals. The deposits have long-term genesis and polygenic character. They are characterized by intensive tectonic and hydrothermal workup of Paleozoic substrate and block structure with small amplitude of vertical displacement. All of them have a two-floor structure, where upper supergene floor has a «background» of lower hydrothermal floor. This fact considerably increases the field of geological prospecting and searching of new oxide-silicate nickel deposits in the Uralian region.
In the Buruktal supergene nickel deposit, iron oxides possess vertical mineralogical zoning (bottom-up): magnetite-maghemite-goethite-hematite. The main rock- and ore-forming mineral in the iron-oxide zone of the deposit is magnetite, presented by three generations: primary relic magnetite, surviving from ultramafic rocks; secondary magnetite, forming at serpentinization process and neogenic supergene magnetite. Supergene magnetite, like a goethite, is nickel ore mineral, containing about 1 % NiO. Under the complex thermal analysis data, maghemite-magnetite and goethite have two main diagnostic maximums: exothermal effect of magnetite, caused by magnetite oxidation to maghemite in the interval 317‑340 °С, displays maximum at 327 °С («magnetite» point), and endothermic effect of goethite, connected with loss of constitutional water of the mineral and its transition to hematite in the interval 269‑296 °С, displays maximum at 288 °С («goethite» point).
