GARNET ULTRAMAFITES AND ASSOCIATED METABASIC ROCKS OF THE BIRYUSA BLOCK (southern Siberia)
T. B. Kolotilina and A. S. Mekhonoshin
Keywords: Garnet ultramafites, lherzolites, metabasic rocks, high-pressure metamorphism
Pages: 1221-1236
Subsection: PETROLOGY, GEOCHEMISTRY, AND MINERALOGY
Abstract
A detailed petrologo-geochemical study of basic and ultrabasic rocks of the Biryusa block has shown that they resulted from metamorphism of weakly differentiated rocks of lhersolite-olivine websterite series and tholeiitic basalts. The temperatures of formation of igneous pyroxenes of ultrabasic rocks are estimated at 1100–1200 oC. The subsequent high-pressure metamorphism at 800– oC and 16-20 kbar produced garnet parageneses in the most ferruginous derivates of ultrabasic magma and in basic rocks.
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