Differentiation and crystallization of magmas
The conclusion that the common igneous rocks form continuous series with respect to bulk compositional variation was an outgrowth of the detailed investigations of the nineteenth century petrographers. However, an understanding of the full evolutionary meaning of these series, in particular with respect to physical chemistry, did not come until the turn of the century. The groundwork for this interpretation was laid by such investigators as Michel-Lévy and J. H. L. Vogt and was carried forward by the careful experimentation and solid deductions of N. L. Bowen and his associates. The ground broken by these early investigators is still being explored today, and recent work has revealed some important facets which were virtually ignored by these and even most comparatively recent investigators as well. One of the most important of recent developments is a growing appreciation of the effect of oxidation, while another is concern with the effect of high total pressures on crystallization, partial melting, and differentiation, with particular reference to the origin of basaltic (or gabbroic) and andesitic magmas. Today these two topics are among the most active areas of petrologic research.
KeywordsEntropy Crystallization Quartz Convection Silicate
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