Cyclic-facies analysis of geological sections at massive sulfide deposits of the Urals

Cyclic-facies analysis of stratified volcanic sequences in the ore-controlling depressions makes it possible to recognize the recurrent and genetically related sets of rock layers that make up micro-, meso-, and mega-scale eruptive cycles (elementary cycle, mesocycle, and megacycle). Massive sulfide ores occupy a specific position in geological sections. They are confined to the upper portions of elementary eruptive cycles and hosted in volcanosedimentary units, indicating their formation during the periods of waning volcanic activity. The elementary cycles are not all accompanied by ore mineralization. The mineralization is most complete in the upper elementary cycles of each eruptive meso- and megacycles.