Thermal Waters Circulation During the Formation of Ore Deposits

Abstract

The paper analyzes processes leading to the formation of gold-bearing sulphide deposits. The study was based on the data available for the territory of Ukraine and other regions. The deposits in question are shown to be associated with post-geosynclinal activation as postulated by concepts of the advection-polymorphism hypothesis. The nature of ore-bearing fluids is analyzed. Even on the ocean bottom helium isotopy points to the presence of mantle components in the fluid. Metamorphogenic and magmatic fluids are obviously involved in the process. An abnormally fast growth of permeability in fault zones during the activation period is shown to have contributed to the formation of deposits. The existence of metalliferous and barren phases of hydrothermal activity is explained. Thermal models of deposits are constructed and diagnostic criteria for their identification determined. The main features of the deposits are associated with faults through which mineralized deep waters circulate. In young deposits, these are: 1. Increased content of metals in soil and plants. 2. Intense heat flow anomalies. 3. High helium isotope ratios, indicating an active process in the Earth's mantle. 4. Zones of high electrical conductivity in the crust and upper mantle. 5. Near the faults, positive anomalies of the gravity field are formed, associated with the transformation of rocks under the influence of heating. The search for gold-bearing sulphide deposits should be continued, considering that the reserves already explored in Ukraine guarantee commercially viable production of over 10 tons of gold per year.