Carbonatites are a unique group of magmatic rocks that contain extremely high concentrations and the world's largest reserves of rare earth elements, niobium, and a number of other industrial metals. The Late Mesozoic Central Asian carbonatite province includes three main regions: Western Transbaikalia, Central Tuva in Russia, and the South Khangai region in Mongolia. The carbonatites form deposits and occurrences of the complex Fe-P-F-(Ba)-(Sr)-REE ores. We studied and correlated the present data about mineral and physicochemical composition evolution in rocks, and provide the characteristics of the processes and fluid regime of the formation of the ore-bearing mineral assembleges of the carbonatites. The main magmatic ore phases are represented by magnetite and siderite (Fe), fluorapatite (P-REE), fluorite (F), and bastnaesite-(Ce) (REE), which were crystallized during fractional crystallization processes from carbonatitic melts at 790-890 °C. The ore-bearing hydrothermal mineral assembleges of carbonates and phosphates of REEs were monazite-(Ce), ancylite-(Ce), bastnaesite-(Ce), parisite-(Ce), synchysite-(Ce), hydroxyl-bastnaesite-(Ce), and the sulphates and carbonates of Ba and Sr-barite, celestite, and strontianite-were formed from the active brine melts of a carbonate-(fluoride)-phosphate-chloride-sulphate-CO2 composition at 680-520 °C. The latter hydrothermal mineralization of carbonates, fluorite, quartz, hematite, gypsum, and phosposiderite was produced from the hydro-carbonate-sulphate-chloride-CO2-H2-N2 fluids at 490-360, 310-275, and 250-100 °C.
|Журнал||International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM|
|Состояние||Опубликовано - 2020|
|Событие||20th International Multidisciplinary Scientific Geoconference: Science and Technologies in Geology, Exploration and Mining, SGEM 2020 - Albena, Болгария|
Продолжительность: 18 авг 2020 → 24 авг 2020