Geophysical research: article

P. Aleksandrov1
Y. Morozov2
A. Kulakovskij2
M. Matveev2
A. Smulskaya2
Y. Sokolova2
1 Geoelectromagnetic Research Center of the Schmidt Institute of Physics of the Earth RAS
2 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences
Journal: Geophysical research
Tome: 21
Number: 1
Year: 2020
Pages: 5-23
UDK: 550.37; 551.243; 551.254; 551.164
DOI: 10.21455/gr2020.1-1
Full text
Keywords: georadar profiling, electrical conductivity, structure of metamorphic strata, cover-basement system, Northern Ladoga region
Аnnotation: The results of studying the subsurface structure of consolidated metamorphic strata using georadar profiling conducted in the metaterrigeneous Paleoproterozoic Ladoga complex of the southeastern part of the Baltic Shield are presented. In the areas with a detailed study by geological methods of the fractured-folded structure, three methodological problems were solved: 1) the identification of consolidated crystalline rocks of the Ladoga complex under the cover of loose deposits; 2) depth tracking of surface elements of faults and folded structure; 3) an assessment of the possible causes and factors that determine the properties contrast of the rock structure elements visible in radargrams by dielectric constant and/or electrical conductivity. The possibility of determining by georadar method the position of the consolidated rocks surface hidden under loose deposits is shown. A fairly high degree of compliance of the structure mapped on the surface with the style of the structural pictures on the profiles is obtained. Based on the analytical study of the composition of rocks and the processes of their mineral-material transformations during folded and fracture deformations in the profiling areas, the role of a number of structural-material factors in the manifestation of the increased conductivity and dielectric permittivity of some rocks in creating the corresponding section contrast is assessed, which is fundamentally important for interpretation of received radargrams.