Decompaction of metamorphic rocks under thermodynamic conditions of the Earth crust (experimental data)
A connection velocity—density inherent to the rocks of deep crust horizons is widely used while plotting concordant model of the Earth lithosphere with the methods of complex interpretation of geophysical data seeking for concordance of rated wave and gravity fields with the observed ones. Materials of experimental studies of elastic-density parameters of rocks under different thermobaric conditions of experiments, in particular, the values of density given in this work, complement and readjust information known before on relations of velocity and density of rocks at different depths considerably. Complex dependences ρ=f (РТ) have been shown for the first time with the areas of density inversion identified — thermodynamic decompaction of rocks, which have to be taken into account in petro-density thermobaric modeling of deep horizons of the earth crust. Zones of decompaction of lithosphere mineral material quite probably exist under present-day thermobaric conditions in the earth crust at the depth 5—15 km, they are characterized by decrease of density up to 0,02 g/cm3 and can produce horizons from 5 to 10 km thick. Rock decompaction is as a rule connected with structural transformations of substances stipulated by opposite per se phenomena of alteration of voluminous temperature expansion of minerals and their compressibility under thermobaric conditions of corresponding depths. Horizons of decreased density (by experimental data) as zones of low seismic velocities are sensitive to temperature regimes of the earth crust. While deep thermal flow increases density of rocks decreases, their ability to decompaction arouses, their permeability and absorbability rise, i.e. the process of mixing of fluids becomes more active and, as a result, metamorphic transduction of rocks takes place. In other words, zones of decreased VP and ρ are the most active horizons of contemporary geologic-geophysical transformations of mineral medium of the earth crust. Their availability may be criteria for search of mineral deposits because they are the most permeable for migrating mineral media in the earth crust.
Full Text:PDF (Русский)
Balashov, D. B. (1987). Volume compressibility of solids. In E. V. Zolotykh (Ed.), Research in the field of high pressures (pp. 272—295). Moscow: Izdatelstvo Standartov (in Russian).
Berch, F. (1965). Solid body under high pressure. Moscow: Mir (in Russian).
Belikov, B. P., Aleksandrov, K. S., & Ryzhova, T. V. (1970). Elastic properties of rock-forming minerals and rocks. Moscow: Nauka (in Russian).
Burtnyy, P. A., Korchin, V. A., & Karnaukhova, E. E. (2013). Modeling of the real composition of deep horizons of the earth's crust (a new concept of interpretation of geophysical data). Saarbrücken: LAP Lambert Akademic Publishing (in Russian).
Geguzin Ya. E., & Krivoglaz M. A. (1971). Motion of macroscopic inclusions in solids. Moscow: Metallurgy (in Russian).
Starostenko, V. I., & Gintov, O. B. (Eds.). (2013). Kirovograd ore district. Deep structure. Tectonophysical analysis. Deposits of ore minerals. Kiev: Galaktika (in Russian).
Kobranova, K. N. (1986). Petrophysics. Moscow: Nedra (in Russian).
Krasovsky, S. S. (1981). Reflection of the dynamics of the Earth's crust of the continental type in the gravitational field. Kiev: Naukova Dumka (in Russian).
Korchin, V. A. (2015). Low velocity zones of thermobaric origin in the crystalline crust. Geofizicheskiy zhurnal, 37(5), 46—65. doi: https://doi.org/10.24028/gzh.0203-3100.v37i5.2015.111145 (in Russian).
Korchin, V. A. (2013). Low velocity zones in the Earths crust are perspective horizons of deep hydrocarbons localization. Glubinnaya neft, 1(8), 1099—1116 (in Russian).
Korchin, V. A. (2011). Petrophysical features of zones of low seismic velocities in the earth's crust and their thermobaric instability. Proceedings of the XVII All-Russian Conference with international participation “Problems of seismotectonics” (pp. 273—277), Moscow, September 20—22.
Korchin, V. A. (2007). Structural features of the mineral environment in the PT-conditions of various depths of the Earth's crust. Geofizicheskiy zhurnal, 29(3), 49—77 (in Russian).
Korchin, V. A. (2013). Thermodynamics of crustal zones of low seismic velocities (new scientific hypothesis). LAP Lambert Academic Publishing (in Russian).
Korchin, V. A. (2014). Thermobaric modeling of anomalies of increased porosity in rocks of the Earth's crust — horizons of possible migration and localization of deep hydrocarbons. Glubinnaya neft, 2(9), 1434—1448 (in Russian).
Korchin, V. A. (2012). Elastic-density thermobaric stratification of the lithosphere, crustal zones of low seismic velocities. Proceedings of the III tectonophysical conference “Tectonophysics and topical issues of Earth sciences” (Vol. 2, pp. 390—393). IPE RAS, Moscow, 8—12 October (in Russian).
Korchin, V. A., Burtny, P. A., & Karnaukhova E. E. (2011). Petrophysical modeling of Earth's crust sections with zones of low seismic velocities. Proceedings of the X International Conference “Geoinformatics: Theoretical and Applied Aspects”. Kiev, Р056, СD-ROM (in Russian).
Korchin, V. A., Burtnyy, P. A., & Kobolev, V. P. (2016). Zones of decompaction of the Earth's crust of the central part of the Ukrainian Shield (according to materials of petrophysical and seismogravitational modeling). Geofizicheskiy zhurnal, 38(3), 84—99. doi: https://doi.org/10.24028/gzh.0203-3100.v38i3.2016.107781 (in Russian).
Korchin, V. A., Burtnyy, P. A., & Kobolev, V. P. (2013). Thermobaric Petrophysical Modeling in Geophysics. Kiev: Naukova Dumka (in Russian).
Lebedev, T. S., Korchin, V. A., Burtnyy, P. A. (1989). Geophysical applications of the results of the RT study of the elastic characteristics of rocks. In Properties and state of mineral matter in the interior of the Earth. Moscow: Nauka (in Russian).
Lebedev, T. S., Kornietz, D. V., Shapoval, V. I., & Korchin, V. A. (1972). Elastic properties of rocks at high pressures. Kiev: Naukova Dumka (in Russian).
Lebedev, T. S., Korchin, V. A., Savenko, B. Ya., Shapoval, V. I., & Shepel, S. I. (1986). Physical properties of mineral matter in the thermobaric conditions of the lithosphere. Kiev: Naukova Dumka (in Russian).
Lebedev, T. S., Korchin, V. A., Savenko, B. Ya., Shapoval, V. I., Shepel, S. I., & Burtnyy, P. A. (1977). Determination of Petrophysical Characteristics by Samples. V. N. Dakhnova (Ed.). Moscow: Nedra (in Russian).
Petrophysical studies with high RT parameters and their geophysical applications. (1988). Kiev: Naukova Dumka (in Russian).
Raider, E. (1987). Fluid inclusions in minerals (Vols.1-2). Moscow: Mir (in Russian).
Clarke, C. Jr. (Ed.). (1969). Handbook of physical constants of rocks. Moscow: Mir (in Russian).
Korchin, V. A. (2006). Thermobaric Seismic Stratification of the Lithosphere. 12 International Symposium on Deep Structure of the Continents and their Margins. September 24—29, 2006. Shonan Village Centre, Hayama, Japan, NHA-P02, CD-ROM.
Korchin, V. (2010). Low velocity zones in the Earth’s crust. Geofizicheskiy zhurnal, 32(4), 70.
Кorchin, V. (2017). Anomalies of low density in the crystalline crust of thermobaric origin: a new insight into migration and localization of hydrocarbons. Monograph 72: Oil and Gas Exploration: Methods and Application (рр. 237—257). American Geophysical Union, Wiley.
Korchin, V. А., & Karnaukhova, E. E. (2007). Effect of mineral content of granitoids of the Ukrainian shield on the change of their elastic parameters in different thermobaric conditions of the lithosphere (by experimental data). XXIV IUGG General Assembly «Earth: our changing planet», July 2—13, 2007. Perugia, Italy, SS001, CD ROM.