Elastic-anisotropic properties of garnet granulites from the lower crust of the belomorian mobile belt: Results of experimental study

摘要

The elastic-anisotropic properties of fifteen samples of garnet granulites from xenoliths in the diatreme on Elovyi Island, in Kandalaksha Bay in the White Sea are investigated. The PT-conditions of the formation of these rocks correspond to a depth of 25-40 km, which is the current depth of the lower crust in the region. According to acoustopolariscopy, the elastic anisotropy of these deep rocks is relatively low. The average seismic P and S velocities corresponding to the in-situ PT-conditions are 6.5-6.7 km/s and 3.7-3.8 km/s, respectively. It is shown that the garnet content in the deep-seated rocks can be estimated from the seismic data. According to the obtained results, the formation of the structural and textural pattern of the lower crustal rocks in the region was poorly affected by the paleotectonic factors.