Vestnik Otdelenia nauk o Zemle RAN VOL. 2, NZ6024, doi:10.2205/2010NZ000042, 2010

Physical and mechanical properties of granitoids of different genetic types

Myasnikova O. V., F. F. Gorbatsevich, V. A. SHekov, O. M. Trishina, M. V. Kovalevskij

Abstract

Article examines the composition, structure, physical and mechanical properties of some granitoids of different genetic types of Karelia, located within the Svekofenian mobile belt and Karelian geoblock, and the prospects for their use as building material.

The dependence of the average density of granitoids on the composition and content of the feldspars and the presence of dark-colored minerals was ascertained. Rocks with high content of sodium-calcium feldspar and with presence of dark-colored minerals are denser.

It was observed that microcracks in the rock along with the mineral composition, grain size and shape of the main rock-forming minerals are one of the important factors affecting the strength of the granitoids and determining their practical use. Taking into account that water absorption in studied samples can be attributed to the presence of microcracks in the igneous rocks, we can assume that low values of anisotropy parameters obtained for the rapakivi granites (phase IV) from Salmi massive with high values of water absorption may be an indication of rather chaotic orientation of microcracks in these samples. Samples of granite rapakivi (phase I) of Salmi massive i.e. vyborgity, have noticeably high values of water absorption and clearly expressed anisotropy, which may indicate that microcracks in the rock have definite orientation.

Received 28 April 2010; published 5 June 2010.