DEVELOPMENT OF COMPOSITION HETEROGENEITIES IN MINERALS WHILE THEIR METASOMATIC GROWTH AND SUBSTITUTION (BY EXAMPLE OF WOLFRAMITE SCHEELITIZATION)

摘要

Some regularities in development of microheterogeneities in mineral composition are demonstrated for example of wolframite, quartz and fluorite substituted by scheelite, with use of Cathodoluminescence and microprobe analysis. There are, at the front line of wolframite substitution by scheelite, the microlocalities of intensive redistribution of elements due to their irregular diffusion towards the substituted phase boundary. From the other side, expanding scheelite inherites components of the primary wolframite; later it will clean itself from them partly by recrystallization and joining of individuals. Morphological features of the newly formed mineral segregations show dependence on the degree of similarity between compositions of the new and primary minerals: the closer similarity is the weaker faceting of the new mineral becomes.