GEOLOGY, CHEMISTRY, AND GENESIS OF Ba-Sr-BEARING (
N.V. Vladykin and I.I. Tsaruk*
Institute of Geochemistry, Siberian Branch of the RAS, 1a ul. Favorskogo, Irkutsk, 664033, Russia
* Sosnovgeologiya Enterprise, 53 ul. Gogolya, Irkutsk, 664039, Russia
Keywords: Carbonatites, alkaline magmatism, differentiation processes, isotope geochemistry
Pages: 315-330
Abstract
The Malyi Murun Massif is a unique rock formation: This is the largest alkaline K-agpaite massif having no analogs in the world. Almost all its rocks are promising for various ores. Therefore, it is of great importance to exactly reconstruct the subsequence of magmatic events here, elucidate the factors responsible for the great variety of rocks in the massif, and determine the PT-conditions of their formation.
The proposed new scheme of magmatism of the Murun Massif explains the formation of a complete series of K-alkaline rocks - from alkaline-ultrabasic through basic and normal to silicic (alkali granites) - and a residual silicate-carbonate differentiate here. We suggest that these rocks resulted from magmatic differentiation and liquid segregation of a peralkaline magma. The residual fluxed melt is also subjected to segregation; it gave rise to unique charoite rocks and
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