Geological phenomenon of the «Yalguba ridge variolites» from F. Yu. Levinson-Lessing till present days: mineralogical-geochcmical aspects
Svetov S. A., Chazhengina S. V.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2017. V. 146. N 2. P. 1-17
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Language: Russian
Abstract
The Yalguba ridge in Karelia is a unique geological object to study Paleoprolerozoic variolitic lavas. The prominent Russian petrologist F. Yu. Levinson-Lessing was the first researcher who described them in details (1884). The present paper displays results of their up-to-date detail mineralogical and geochemical investigation. There are distinguished several generations of pyroxenes characterizing as main magmatic, so metamorphic zoning, which reflect variations of the melt composition and thermodynamic parameters during the crystallization process. Contents of main and trace elements were estimated in varioles and in the rock matrix. On the base of compared results of mineralogical and geochemical analyses, there are made conclusions about the consequence of crystallization of the immiscibile melts and the role of contamination the basalt melt by crustal material.
Key words: Paleoproterozoic variolites, picrite lavas, pyroxenes, zoning, magmatic liquation.
