TIME FACTOR IN THE FORMATION OF HYDROTHERMAL DEPOSITS - PERIODS, EPOCHS, MEGASTAGES, AND STAGES OF ORE FORMATION

The evolution of ideas in the last few decades on the duration and seq uence of the development of mineral parageneses (epochs, megastages, a nd stages) during the mineral deposit formation is reviewed. The autho r concluded that the prolonged period of the prehistory of the formati on of economic ore accumulations is very important. This is also very important for understanding the nature of metallogenic specialization, the extent of ore-bearing potential, and for distinguishing evolution ary series of ore deposits. By the example of gold deposits, the relat ions between the megastages and stages of the evolution of postmagmati c solutions and megastages and stages of ore mineralization reflecting pulsation in the course of ore genesis are discussed. The main sequen ce in the development of mineral parageneses, steadily preserved in va rious types of ore deposits, is regarded as an instrument for the anal ysis of the megastage and stage of ore formation and evolutionary syst ematics of mineral deposits.