The mineralogy of kimberlites is a result of crystallization of the parent magma over pressure and temperature conditions ranging from those of the upper mantle to those of the upper crust, and is complicated by the presence of the enigmatic megacryst suite and numerous mantle-derived xenocrysts. The approach adopted in this work is to describe the minerals approximately in their paragenetic sequence of formation as determined by petrographic studies (Chapter 3). In some cases, e.g., mica, olivine, and garnet, it is impossible to draw a firm distinction between a megacrystal or phenocrystal status; consequently it has been found convenient to describe megacrysts and phases of undoubted primary origin together. This approach facilitates comparisons and avoids repetition. Minerals of minor importance or of uncertain paragenesis are described in the latter sections of the chapter.
KeywordsCompositional Trend Lherzolite Xenolith Yakutian Kimberlite Rare Earth Element Distribution Pattern Lamellar Ilmenite
Unable to display preview. Download preview PDF.