UP-TO-DATE BLOCK STRUCTURE OF CENTRAL ASIA IN GEOPHYSICAL FIELDS

• Main Authors: Gatinsky, Yury, Prokhorova, Tatiana, Rundquist, Dmitry, Vladova, Galina
• Format: Text
• Language: unknown
• Published: Автономная некоммерческая организация Научно-издательский Центр "Пространство и Время" 2013
• Subjects: CENTRAL ASIAN TRANSIT ZONE,AREAS OF ACTIVE FAULTS AND TECTONIC ACTIVITY,INTERBLOCK ZONES,MANTLE PLUME,LITHOSPHERE THICKNESS,CRUST THICKNESS,MAGNETIC FIELD ANOMALIES,HEAT-FLOW ANOMALIES,GRAVITY ANOMALIES,GRAVITATIONAL LINEAMENT,ЦЕНТРАЛЬНО АЗИАТСКАЯ ТРАНЗИТНАЯ ЗОНА,ЗОНЫ АКТИВНЫХ РАЗЛОМОВ И ТЕКТОНИЧЕСКОЙ АКТИВНОСТИ,МЕЖБЛОКОВЫЕ ЗОНЫ,МАНТИЙНЫЙ ПЛЮМ,МОЩНОСТЬ КОНТИНЕНТАЛЬНОЙ КОРЫ,МОЩНОСТЬ ЛИТОСФЕРЫ,АНОМАЛИИ МАГНИТНОГО ПОЛЯ,АНОМАЛИИ ТЕПЛОВОГО ПОТОКА,ГРАВИТАЦИОННЫЕ АНОМАЛИИ,ГРАВИТАЦИОННЫЙ ЛИНЕАМЕНТ; Okhotsk; okhotsk sea
• Online Access: http://cyberleninka.ru/article/n/up-to-date-block-structure-of-central-asia-in-geophysical-fields; http://cyberleninka.ru/article_covers/14509360.png

During 2004—2009 authors worked out a problem of up-to-date geodynamic heterogeneity of the Eurasian continent with establishing the north Eurasian lithosphere plate and some transit zones between it and neighboring plates. The zones consist of numerous blocks limited by active faults, and what’s more the maximal tectonic activity coincides with interblock zones. Since 2009 we fulfilled the closer definition of block boundaries and interblock zones in central Asia. The majority of active faults and epicenters of the strongest earthquakes coincide with them, so their detail investigation and correlation with different geophysical fields are important for establishing the level of the seismic activity in this region. In the seismic energy field the maximal volume of energy release in plate boundaries and interblock zones of the central Asian transit zone. In the field of up-to-date tectonic stress the compression distinctly predominates in this transit zone and changes partly on extension and slipping with extension in the east Asian zone. High positive anomalies of the magnetic field (up to +50…+100 nT ) characterize the great part of interblock zones and large faults limited them. The gravitational field of the most part of central Asia in the Bouger reduction is characterized by negative values up to –50…-150 mGal. The distinct extending gravitational lineament crosses in NNE direction the significant part of the continent from the Bacbo Bay to the Okhotsk Sea coast with changing of above mentioned negative values by more positive in the east. This change is connected with the sharp decreasing of the continental crust thickness. Heat-flow values increase up to 80-100 μW/m 2 and more in interblock zones, which are situated in boundaries of Hangay, Amurian, Tibet’s, and Tarim blocks as well as in some inner continental rifts. Some of heat-flow anomalies can be connected with mantle plumes under Hangay and north part of the Amurian Block. The crust thickness changes in central Asia from 25-30 km in the east up to 50—75 km in the west under Tibet and neighboring blocks. The lithosphere thickness changes in the same direction from 60—80 km up to 120—150 km, but it decreases up to 100 km and less under inner continental rifts coinciding with interblock zones. The direction of the P and S -waves anisotropy shows within the great part of the region the coupling deformation in the lithosphere upper mantle and crust. Differently directed vectors of horizontal displacement are established in the crust and upper mantle only east of the east Himalayan syntax indicating decoupling these layers under the influence of the Hindustan-Asia collision and “a threshold” of the SE China thick lithosphere in its boundary with Tibet.