Material depth models of the Ukrainian Shield

• Дата: 2025
• Автори: Burtnyi, Petro, Karnaukhova, Olena, Kobolev, Volodymyr
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: S. Subbotin Institute of Geophysics of the NAS of Ukraine 2025
• Теми: Ukrainian shield; profile; seismic velocity; pressure; temperature; decompaction; density; modelling; model columns
• Онлайн доступ: https://journals.uran.ua/geofizicheskiy/article/view/333068
• Назва журналу: Geofizicheskiy Zhurnal

Deep composition models have been constructed by the method of petrophysical thermobaric modeling for individual megablocks of the Ukrainian Shield. The method is intended for comparison the data of deep seismic sounding and experimental study of physical parameters at high pressures and temperatures of rock samples that form the studied megablocks. The validity of regional deep thermobaric petrophysical constructions is confirmed by the existence of appropriate criteria of similarity. With petrophysical thermobaric modeling, the equality of average values of pressure values and temperatures in laboratory and natural conditions is enough to accept them comparable. This basic principle is at the heart of the method. The second principle of the petrophysical thermobaric modeling is based on the differentiation of physical parameters of various mineral environments, depending on their petrological characteristics, including composition, genesis, structural and textural features, and other factors. Individual РT protocols of experiments were developed for each studied area of the Ukrainian Shield. Within the Ukrainian Shield, it has been established that the Earth’s crust is usually composed of granite-gneisses underlain by rocks of intermediate composition (charnockitoides, enderbites or diorites) and, then, down to the Moho interface, by mafic rocks (mafic granulites, gabroides) and ultra-mafic (рyroxenitеs) rock соmposition. All models record low velocity zones (zones of thermobaric decompaction of rocks) usually located at depths of 5—15 km. The predicted of such zones correspond to the intervals experimentally detected seismic wave inversions and densities of the studied rock samples of the Ukrainian Shield depending on the pressure and temperature according to the depth of occurrence.