Browse

Chromium spinel is identified as macrocrystals and rock-forming mineral of groundmass in kimberlites, composing the Manchary and the Aprelskaya pipes of the Khompu-May kimberlite field (Central Yakutia). Spinel assemblage of every pipe is individual. Chromospinellides of mesostasis of the Manbchary pipe crystallized in two stages. At the first stage, groundmass spinel crystallized until phlogopite was formed, at the second stage ? at the same time with mica, removing aluminum and magnesium form the melt. Kimberlit...

Barium phlogopite is found as rock-forming mineral of groundmass in kimberlites, composing the Manchary and Aprelskaya pipes of the Khompu-May kimberlite field (Central Yakutia) and in glimmerite xenoliths, occurring in the Manchary pipe. Glimmerite xenoliths are composed of differently oriented phlogopite plates (up to 0,5 cm). Reversed zoning is typical for the most mica grains regarding BaO content. BaO content reaches 14,6% in central zone, and 4,8% in marginal zone. Mesostasis of kimberlites has phlogopite-se...