Volume 2 – Issue 1 – 2021

Original Research Article

Elastic-Anisotropic Properties Of Rocks Of Different Composition And Metamorphism Facies Of The Northeastern Baltic Shield

F.F.Gorbatsevich, O.M.Trishina, M.V.Kovalevskiy
Russian Academy of Sciences, Kola Science Centre, 184209, Apatity, Murmansk region. 14 Fersman Str., (RUSSIA)

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ABSTRACT – DOI: https://dx.doi.org/10.47204/EESR.2.1.2021.009-086

Using rocks composing the Matert Formation of the Pechenga complex in the sections of the Kola superdeep borehole (SG-3) and Finnish Outokumpu drill hole, massifs in the vicinity of Lake Chudzyavr and the River Tuloma, xenoliths and volcanic pipes (Elovy Island) as an example, geologic and geochemical peculiarities, metamorphism and physical properties of rocks from the prehnite-pumpellyite to the granulite facies have been studied. It is shown that the acoustopolariscopy method applied in the researches allows distinguishing rocks of different metamorphism facies (from the prehnite-pumpellyite to the amphibolite facies). The study showed that the rock densities increase from the prehnite-pumpellyite to the amphibolite facies (the Earth’s surface). The rock density under depth conditions increases from the prehnite-pumpellyite to the granulite facies. Rocks of the epidote-amphibolite and amphibolite facies (the Earth’s surface) showed the lowest velocities of compression waves. The values of velocity as well as density under depth conditions tend to increase from the prehnite-pumpellyite to the granulite facies. High anisotropy indices were observed for the high-temperature amphibolite facies. The data obtained (density, velocity characteristics, elastic moduli and Poisson’s ratios) reflect the actual properties of the massif rocks and can be used for geophysical investigations and technical calculations.