GOLD DEPOSITS OF THE UKRAINIAN SHIELD (UKRAINE)

New data on the geology of Ukrainian Precambrian gold deposits are pre sented. Recent studies have shown that there are at least three geneti c types of the deposits, which originated as a result of the evolution of the Earth's crust in the Early Precambrian. The first type is mani fested in the Pri-Dneprov Block (domain) and related to the formation and alteration of greenstone belts. The second type is widespread on t he central Ukrainian Shield (US) and related to the gold redistributio n in the Upper Archaean to Lower Proterozoic clastogene rocks. The thi rd type is localized in the Middle Bug region and related to the crust -upper mantle interaction in the Early-Late Proterozoic. The deposits formed in several phases within a wide temperature range (500 to 50 de grees C) and at pressures of 250 to 50 MPa. The redistribution of gold resulted in an increase of its fineness. These phases were dated with in the time range 2900-400 Ma. U-Pb isotopic systems are sensitive to thermal and pressure conditions and provide reliable datings of geolog ical events. Gold accumulation was discrete and well correlates with t ectonic and metasomatic activization processes. Microprobe analyses in dicated that native gold and gold-bearing minerals (sulfides, quartz, amphiboles) contained admixtures of bismuthite, cuprite, native copper , cinnabar, argentine, acanthite, orpiment, bravoite, chalcosine, hexa gonal and monoclinic pyrrhotite, antimonite, marcasite, arsenopyrite, native silver, and uranium minerals (ningyoite and brannerite). Sulfur , oxygen, and hydrogen isotope data on the minerals and fluid inclusio ns argue for a metamorphic-magmatic genesis of a fluid. Complex geolog ical, geochemical, mineralogical, and isotope-geochemical studies made it possible to develop the basis for genetic models of gold deposits, determine criteria for exploration of the deposits in various Precamb rian structural and geological settings, and predict new genetic types . Geological exploration revealed the high gold potential of the Ukrai nian Shield and promised a considerable increase of its resources and development of gold mining.