Relevance of the work is in identifing the sources of formation of rocks and ores of the Lubavinsky gold deposit. A characteristic feature of geological structure of the deposit is the close paragenetic relationship of gold mineralization with granodiorites (J2-3) and rocks of the dike complex (J3) (felsites, quartz porphyries, granodiorite-porphyry, diorite porphyrites, lamprophyres) of the Lubavinsky tectonic zone. Identification of spatial, age and genetic relationships of gold mineralization with magmatism is the key fundamental problem of metallogeny. The aim of the work is to discover the petrogeochemical features of rocks and ores, to identify sources of mineralization of the Lubavinsky deposit. Methods. X-ray fluorescence analysis was used (at GIN SB RAS, Ulan-Ude) for determining an element composition of rocks. Content of major elements was determined by the standard chemical method, concentrations of rare earth elements were determined using sorption-atomic-emission spectrometer with inductively coupled plasma (ISP-SAES) (at GIN SB RAS, Ulan-Ude). Determination of oxygen isotopic composition was performed using the MIR 10-30 equipment (at Common User Center, Irkutsk). The authors investigated sulfide sulfur isotopic composition and contents of Au and Ag at CUC SB RAS of multi-element and isotope investigation (Novosibirsk). Results. It was revealed that sulfide-quartz ores of the Lubavinsky deposit have a magmatic source. This is confirmed by the data on the isotopic oxygen content of ore-bearing sulfide-quartz veins, as well as sulfur isotopes of sulphides. The calculated isotope composition of oxygen in the fluid in equilibrium with the quartz of the productive stage (260-205 °C) varies from 2,69 to 10,26%. Most of the calculated values fall within the range of +5,5 - +9,5%, which corresponds to an aqueous fluid of magmatic nature. It was revealed that the fluids that deposited sulfides are characterized by the values of δ34S,% from -0,56 to + 6,44%, which indicates a magmatic source of sulfur. The geochemical features of the intrusive rocks of the Lubavinsky deposit testify to the presence of a mantle component in them, which is confirmed by their correspondence to adakites. The formation of sulfide-quartz veins occurred in relation to evolution of differentiated, differently deep magmatic foci in varying degrees, as evidenced by the features of distribution of rare-earth elements in ores.
|Журнал||Известия Томского политехнического университета. Инжиниринг георесурсов|
|Состояние||Опубликовано - 1 янв 2018|