Aspects of the mineralogy of the Muran alkaline complex, Yakutia, Russia

The Murun complex contains a number of unusual and mineralogically unique rocks. Many of them are problematic in terms of their genesis and petrographic interpretation. These enigmatic rocks include charoite assemblages, as well as unique Ba-Sr-rich carbonatites and alkaline ultramafic dykes referred to as lamproites or lamprophyres.; Charoitites occur in about 25 localities along the southern margin of the Little Murun intrusion. Obtained compositional data for charoite suggests, in general, the empirical formula: (K,Na)3(Ca,Sr,Ba,Mn)5Si 12O30(OH,F)· 3H2O.; The carbonatite bodies are confined to the aegirine-microcline fenite aureole in the southern contact zone of the Little Murun massif with the Precambrian crystalline basement. Three mineralogical types of the studied carbonatites are distinguished: calcite carbonatite (i) Ba-Sr-Ca carbonatite (ii) and phlogopite-calcite carbonatite (iii). In addition, the quartz-feldspar-carbonate rock is classified as a distinct lithological type.; The youngest igneous suite at Murtin is represented mostly by dykes and sills. Studied hypabyssal and volcanic rocks are divided into eight petrographic groups: lamprophyre pseudoleucite syenite, pseudoleucite italite, kalsilite melasyenite, eudialyte-bearing syenite "Potassium-batisite" syenite, lamprophyllite- and barytolamprophyllie-bearing syenite, and aegirinite. (Abstract shortened by UMI.)...