CHEMICAL COMPOSITION OF CARBONATITE MINERALS IN KARASUG DEPOSIT, TUVA

Abstract

Results of electron microprobe analyses (70 determinations) of minerals in the Karasug deposit of complex ores (Fe, F, Ba, Sr, TR, U, and Mo) in Tuva are presented. The chemical compositions and other properties of minerals are characterized taking into account earlier published data for barren ankerite-calcite carbonatites (calcite, ankerite, dolomite, apatite, monazite, parisite, thorite, pyrite, rutile, and strontianite) and ore-bearing fluorite-barite-siderite carbonatites (siderite, fluorite, Ba and Sr sulfates, bastnaesite, hematite, pyrite, molybdenite, uraninite, and muscovite). The inhomogeneity of mineral compositions in dolomite-ankerite, parisite-synchisite, and barite-celestine associations is imaged in reflected electrons. A summary of published data on Ba and Sr sulfates shows that the natural compositions of these isomorphic minerals correspond to the following separate groups: barite-Sr-barite-barytcelestine-Ba-celestine-celestine. Some conclusions are drawn regarding the typomorphic features of the mineral compositions for the carbonatites.