The investigations of the parental melts composition for the ultramafic lamprophyres from the Siberian Craton were provided. This type of alkaline rocks together with carbonatites and kimberlites is unique since it directly carries information about deep mantle processes. There is also industrial significance for such type of rocks, as they are potential sources of niobium, rare earths and many other critical elements. Study of inclusions of melt captured by minerals of alkaline rocks is a modern method of studying the composition of parental melts. The melt inclusions in olivine of ultramafic lamprophyres of the Terina complex (Chadobets upland, Russia) were investigated; as well as the chemical characteristic for the host olivine is presented. Phlogopite, clinopyroxene, calcite, Ca-Na-amphibole, fluorapatite, dolomite, Ti-magnetite and ilmenite were determined as the daughter-phases of the secondary melt inclusions in the olivine macrocrysts. Some melt inclusions also contain halite, anhydrite and probably the xenogenic phases of Fe-Ni-sulphides. Raman spectroscopy revealed the presence of Ca-Na-carbonates, synchysite-(Ce) and CO2 in the melt inclusions. The depth for the captured ultramafic lamprophyre melt was estimated as ~7-12 km according to the CO2 density in the melt inclusions. The mineralogy and melt inclusion investigations provide an opportunity to trace the P-T-X-parameters of the carbonate-rich mantle-derived alkaline melts formation beneath the Siberian craton during the Permian-Triassic Siberian plume activity.
|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