The possible degassing nature of some local structures of concentric and zonal structure on the territory of the Volyn-Podolye plate and the Western part of the Ukrainian Shield and the way of their subsequent study

Abstract

The article considers some specific features of the fracture-block structure of the Podolye and Volyn megablocks of the Ukrainian Shield, as well as the Volyn-Polesye volcano-plutonic belt (within the sheet of M-35-IX — «Kostopol») in connection with the wide deployment of studies on deep hydrogen degassing of the Earth and the search for geological structures in which it can be detected both in the world and in Ukraine. Particular attention is paid to the Goryn, Rovno, Nemirov, Zvizdal-Zalesye and some other fault zones, within which from a new point of view already known and highlighted other local structures of zone-concentric construction have been distinguished, which can be associated with a certain probability with the processes of tubular degassing of the mantle.

Local signs of pipe degassing structures include the presence of anomalies of magnetic and gravitational fields of isometric form and as well as a specific internal concentric-zonal structure; integral high electrical conductivity anomalies; small amplitudes of troughs on the present day surface, the presence of native copper and other metals mineralization in the contours of the supposed structures; carbonic manifestations, hydrochemical anomalies of uranium and emanations of radon. These signs within the Premesozoic foundation of the «Kostopol» sheet mostly corresponding to Telcha, Golovino and Gorodets zone-ring structures, have been described in detail in the article. Previously, they were classified as paleovolcanic plutonic structures associated with tectonic activation zones, although the absence of direct signs of deep magmatism was ignored in them. An important sign of cold tubular degassing processes with the accompanying phases of pulse explosion in these structures is the steep and even subvertical fall of the rocks of the ring frame, which usually make up a horizontal cover within the area.

The Nemirov and Zvizdal-Zalesye fault zones, which limit the Podolye megablock from the southeast and east, include, respectively, the Ilyinets and Belilovo local ring structures, which are considered as astroblemes by some researchers. This ignores the fact that the Ilyinets structure was being formed over 50 million years, and Carbonaceous manifestations as small diamonds and native gold mineralization in gabbro breccia have been installed in the Belilov structure. The presence of signs of both astroblem and endogenous origin of both structures, allows us to give a combination of both mechanisms of their formation, in which the fall of a meteorite initiates the inclusion of endogenous process, in particular tubular deep degassing. In order to study the features of the deep structure of these patterns, it is proposed to conduct a certain additional complex of geological and geophysical research.