1. JGD
  2. All Volumes and Issues
  3. 1(9), 2010
  4. Crust termobaric transformations of mineral matter and connected with them seismic vertical stratification of lithosphere

Crust termobaric transformations of mineral matter and connected with them seismic vertical stratification of lithosphere

JGD.
2010;
Volume 9, Number 1
: 50-56
https://doi.org/10.23939/jgd2010.01.050
Received: October 26, 2010
Authors:
  1. V.A. Korchin
1
Subbotin Institute of geophysics of National Academy of Sciences of Ukraine

In the resent years fragmentary crustal low velocity zones were revealed by DSS profiles at depths of 3-25 km around the Earth. In most cases they are considered as thermodynamical phenomena rather than a result of changing composition when mineral material is transformed by pressure and temperature at the depth of their occurrence. Multimethod laboratory studies of sample show that under PT conditions at 5-15 km depths rocks are subjected to cataclastic and dilatational changes. A major mechanism responsible for this behaviour is a resultant effect of irregular and differently oriented tensions in the sample. In contacts between grains they reach values which exceed the strength limit of individual minerals that destructs integrity medium at a microlevel. Here the rocks are characterized by low Young and shear modules, high brittleness (low Poissons’s ratio), high discompaction (high dilatancy), low thermal conductivity (λ). The inversion zones in most cases well coincide with low velocity zones in the Earth’s crust from DSS profiles. As low velocity zones result from temperature destruction of rocks uncompensated by pressure at 5-18 km depths, іnstability of the crustal thermobaric zones of low velocity result in their episodic occurrence in the crust and their vertical and horizontal migration depending on temperature fluctuations in the crust.

Earth’s crust
longitude wave velocity
low velocity zones
laboratory termobaric investi-gations of rocks
  1. Kobolev V.P., Svischuk I.N., Shapoval V.I., Kar-nauhova E.E. Teploprovodnost nekotoryih gra-nitoidov Ukrainskogo schita v termobariches-kih usloviyah zemnoy koryi // Geofiz. zhurn. – 2007. – 29, # 3. – S. 37–48.
  2. Korchin V.A. Termobaricheskoe petrostrukturnoe modelirovanie zemnoy koryi Ukrainskogo schi-ta i priroda nekotoryih seysmicheskih granits // Materialyi V-h geofizicheskih chteniy im. F.F.Fedyinskogo. – Moskva: GEON – 2003. – S. 83.
  3. Korchin V.A. Strukturnyie osobennosti mineral-noy sredyi v RT-usloviyah razlichnyih glubin zemnoy koryi // Geofiz. zhurn. – 2007. – 29, # 3. – S. 49–77.
  4. Korchin V.A. Korovyie termobaricheskie preobra-zovaniya mineralnogo veschestva i svyazannoe s nimi seysmicheskoe vertikalnoe rassloenie litosferyi / MaterIali naukovoYi konferentsIYi “GeofIzichnI tehnologIYi prognozuvannya ta monI-toringu geologIchnogo seredovischa”. 6-10 zhov-tnya, 2008, LvIv. – LvIv: Spolom, 2008. – S. 36–38.
  5. Kutas R.I. Pole teplovyih potokov i teoretiches-kaya model zemnoy koryi.Nauk. dumka, 1978. ― 140 s.
  6. Lebedev T.S., Korchin V.A. Uprugie harakteris-tiki mineralnogo veschestva v termobariches-kih usloviyah zemnyih nedr // Acta Geodaetica, Geophysica et Montanistica Acad. Sci. Hung. – Budapest: Academiai Kiado. – 1979. – 14, 1-2. – P. 181–226.
  7. Lebedev T.S., Korchin V.A., Savenko B.Ya., Shapo-val V.I., Shepel S.I. Fizicheskie svoystva mineralnogo veschestva v termobaricheskih usloviyah litosferyi. – K.: Nauk. dumka, 1986. – 200 s.
  8. Lebedev T.S., Korchin V.A., Shepel S.I., Saven-ko B.Ya., Shapoval V.I., Burtnyiy P.A. Petro-fizicheskie issledovaniya pri vyisokih RT-parametrah i ih geofizicheskie prilozheniya. – K.: Nauk dumka,1988. – 248 s.
  9. Lebedev T.S., Shapoval V.I., Korchin V.A. Issle-dovaniya vozdeystviya vyisokih temperatur i davleniy na izmenenie skorosti v izverzhen-nyih i metamorficheskih gornyih porodah // Geofiz. sb. AN USSR. – 1969. – Vyip.31. – S. 75-92. – Vyip.32. – S. 5–17.
  10. Lebedev T.S., Shapoval V.I., Korchin V.A., Prav-divyiy A.A. Opredelenie teploprovodnosti mi-neralnogo veschestva po akusticheskim izme-reniyam v razlichnyih termobaricheskih uslovi-yah // Geofiz. zhurn. – 1980. – 11, # 5. – S. 33–39.
  11. Lyubimova E.A. Termika Zemli i Lunyi. – M.: Nauka, 1968. – 279 s.
  12. Naschekin V.V. Tehnicheskaya termodinamika i te-ploperedacha. ― M.: Yzd-vo “Visshaia shkola”, 1969. – 560 s.
  13. Struktura zemnoy koryi Tsentralnoy i Vostochnoy Evropyi. – K.: Nauk. dumka, 1980. – 280 s.
  14. Tripolskiy A.A., Sharov N.V. Litosfera dokem-briyskih schitov severnogo polushariya Zemli po seysmicheskim dannyim. – Petrozavodsk: Karelskiy nauchnyiy tsentr RAN, 2004. – 159 s.
  15. Korchin V.A. Thermobaric Seismic Stratification of the Lithisphere // 12 International Symposium on Deep Structure of the Continents and their Margins. September 24-29, 2006. Shonan Village Center, Hayama, Japan. – NHA-P02.
  16. Korchin V.A, Kobolev V.P, Burtny P.A., Karnau-khova E.E. The thermobaric nature of the low seismic velocities zone’s in the Earth crust // Mezhdunarodnyiy nauchno-prakticheskiy semi-nar “Modeli zemnoy koryi i verhney mantii”. 18-20 sentyabrya, 2007 g. Sankt-Peterburg, Ros-siya. (CD ROM).