Spatial Rhythms in the Data of Super-Deep Boreholes

Abstract

This article continues a study of spatial rhythmic variations of various parameters using spectral-profile analysis. This procedure has been successfully used in the Atlas of Natural Processes. In this study, manifestation of spatial rhythmic variations is considered with the example of vertical profiles composed of P-wave velocity values for three superdeep boreholes: Kola (SD-3), Vorotilov (VDB), and Ural (SD-4). Using wavelet analysis, we estimated the periodicities in the velocity variations and represented the seismoacoustic models of the SD-3, VDB, and SD-4 geological sections as a set of blocks of varying size in the upper part of the Earth’s crust. These blocks reflect the influence of different geodynamic processes at various depths. It was found that the hierarchical sequence of the average vertical sizes of the blocks corresponds to the hierarchical model of the geophysical medium. The geodynamical processes, which resulted in cyclic variations in P-wave velocities in the geological sections of the Kola (SD-3), Vorotilov (VDB), and Ural (SD-4) superdeep boreholes include: alternating epochs of volcanic activity and sedimentation, tectonic movements, impact events, penetration of intrusive bodies and amphibolite dikes in the intervals of relatively weaker rocks, and metamorphic and metasomatic alteration of rocks. Study of the sections of the superdeep boreholes can be considered, to some extent, a real-scale simulation of the crustal structure of the Earth up to large depths. Studies have shown that variations in the physical properties of crustal rocks and the hierarchical sequence of the average vertical sizes of blocks have common properties of cyclic processes involved in the “self-organization” environment.