Reflection of sequence of geodynamic processes in geological structure of the Bug area
Journal Title: Геофизический журнал - Year 2019, Vol 41, Issue 3
Abstract
The age of formations composing granulite blocks of the Ukrainian Shield is a pro-blem for disputes. In order to ascertain the primary genesis and conditions of transduction of the Bug area rocks it is proposed to find out how was deep process realized according to composition of magmatic and chemogenic-sedimentary rocks. Description of formations was used and sequence of geological events, given in the paper [Venidictov, 1986] for the Upper Bug area. During the period that began not later than 2.5 Ga and lasted up to 2.0 Ga three tectono-magmatic cycles happened that can be compared with a regime “folded area”. Application of over-all schemes allows to ascertain composition and temperatures of melts and fluids sup-plied to the crust (thermodynamic regime), and to appraise the character of interactions (metasomatic substitution, crystallization, melting-dissolution etc.) between deep material (of the known composition and temperature) and crust material at the ascertained depth (with known lithostatic pressure and temperature). Regime “folded area” is characterized by magmatic rocks generated at depths 220, 150, 100, 50 km. Underlaying of the crust by mantle (ultrabasic) melts and replenishment of melting layers with their upper edge at depths 50 and 20 km, occurs repeatedly, that assumes complication of ba-sic regime. It has been determined that in the Bug area temperatures and pressures of metamorphic transformations exceeded those ones needed for production of the layer of partial melting in the crust. To present-day erosion section the level of asthenosphere position, where granites attached to the berdychiv complex was drawn. Sequence of occurrence was replaced by the order of incorporation and substitution. Primary sedimentary rocks were not preserved and there is no relation between occurrence of rocks and their age.
Authors and Affiliations
O. V. Usenko
Keywords
Related Articles
- EP ID EP604808
- DOI 10.24028/gzh.0203-3100.v41i3.2019.172425
- Views 75
- Downloads 0
Secular variations of the geomagnetic field on litosphere plates of the Earth
The dependence of the value and sign of the geomagnetic secular variations (SV) refined of 3- and 11-year components on the position of observatories at different tectonic plates is investigated. The observatories of the...
Problems of Precambrian paleomagnetism on the territory of Ukraine
Some problems of paleomagnetic research of the Precambrian rocks of Ukraine are considered. The results of paleomagnetic researches of the Proterozoic rocks of the Ukrainian Shield, Ediacaran traps of Volyn and sedimenta...
Peculiarities of the geomagnetic field secular variations at the 20th solar activity cycle
The decrease of solar and; correspondingly; geomagnetic activities at the 20th cycle has reflected on the secular variations of the geomagnetic field. On the continental magnetic observatories of the Earth north hemisphe...
The nature of inclined seismic boundary in the Earth crust of the Scythian plate along the DOBRE-5 Profile
Geological and tectonic interpretation of high-speed seismic model along the profile DOBRE-5 elaborated in 2011 by DSS method (wide-angle refraction and reflection (WARR)) with the main aim of clarifying the structure of...
Magma Chamber Associated to Deep Faults in Copahue Active Volcanic Complex, South America, Suggested by Magnetotelluric Study
Magnetotelluric studies were carried out in 1993 and 2008 inside the caldera of Copahue Volcanic Complex, located in South America, at the border between Chile and Argentina (37°45ʹ S; 71°10.2ʹ W). The main effusive cent...