SOURCES OF ORE-BEARING FLUIDS Au, Mo, W AND Pb-Zn OF EASTERN TRANSBAIKALIA DEPOSITS (ACCORDING TO THE RARE EARTH ELEMENTS DISTRIBUTION)
The relevance of the work is in the fact that the presented data on the sources of ore-bearing fluids of different types of Mesozoic deposits of Eastern Transbaikalia, based on the analysis of distribution of rare-earth elements and indicator ratios of rare and rare-earth elements in ores, will provide new knowledge about the nature of ore formation. The aim of the work is to determine the features of distribution of ore and rare-earth elements in ores of various types of deposits, formed due to different depth ore fluids. Methods. To determine the elemental composition of rocks, the X-ray fluorescence method was used (GIN SB RAS, Ulan-Ude). The concentrations of rare-earth elements were determined by the method of sorption-atomic emission analysis with inductively coupled plasma (GIN SB RAS, Ulan-Ude). Result. It was established that the sources of gold ores of Aleksandrovsky, Itakinsky, and Kariysky, Bugdainsky and Zhirekensky molybdenum, Bukuinsky tungsten deposits were not of uniform depths and differentiated to various extent ore-bearing magmatic sources. The presence of multiple sources of mineralization is confirmed by the indicator ratios Eu/Sm, U/Th, Hf/Sm and Nb/La. It was revealed that in gold deposits in ores formed from magmatic sources of the upper continental crust, relative to the ores, the sources of which were ore-bearing fluids of the lower continental crust, there are elevated concentrations of chalcophile elements (Cu, Ag, Bi, Sb, Pb) and lower concentrations of lanthanides. In molybdenum deposits in ores from magmatic sources of the lower continental crust, in comparison with the ores formed in the upper continental crust, there are elevated concentrations of both chalcophilic elements and lanthanides. In molybdenum deposits in ores from magmatic sources of the lower continental crust, in comparison with the ores formed in the upper continental crust, there are elevated levels of both chalcophile elements and lanthanides. In polymetallic deposits and parts of molybdenum and tungsten deposits, there was only one ore-bearing magmatic source operating in the upper or lower continental crust.