Authors	Definitions, types and features of OFS
Smirnov, [1]	In relation to the genesis of ore deposits the OFS are regarded as combinations of interrelated geological processes, circumstances and situations, defining conditions of their formation.
Krivtsov, [2]	The OFS generally unite: sources of ore material, transporting agents and energy; ways of transportation of ore material carriers; areas of unloading of carriers and accumulation of ore material; dispersal areas of transporting agents. Characteristic features of the OFS—multistage character of ore material concentration, polygenic and polychronous ore-formation, its discontinuity.
Ivankin, Nazarova, [3]	There was an OFS typization suggested. There are heterogeneous metallogenic rows, considering the diversity of mantle-crustal interactions and geodynamic situations, magmatism and forms of the Earth’s degassing: mantle orthomagmatic, magmagenic mantle-crustal, magmagenic intracrustal, intratelluric (orthopneumato-hydrothermal), intratelluric with the “cold” type of fluid evolution (“naphthometallogenic”).
Konstantinov, [4]	The formation of ore deposits is defined by the integrated effect of multilevel OFS in the Earth’s crust. There are OFS defined, which are zonally distributed across the section of the crust (top-down): lithogenesis, geothermal convection, ultrametamorphism and magma generation, plastic flow and lateral metal migration.
The metallogenic code of Russia, 2012	The OFS are connected in time and space: sources of energy, ore material and transporting agents (ore-generating geological formations); ways of transportation of ore material and areas (environments) of its accumulation (ore-bearing and ore-generating geological formations). According to the character and the features of ore material carrier ore-forming systems are divided into three main groups—hydrogenous (exogenous), hydrothermal (endogenous) and melt (magmatic).