Within the frameworks of the RFBR Project № 14-05-00545, we have completed a 3-year research cycle on the theme “Specificities of deep structure and geodynamics of junction zones of Central Asia mountain structures of different ages (using an example of Pamir-Gissar-Alay System)”. The main purpose of the research is to define geological and geophysical characteristics of geodynamic system of interaction of the two largest mountain areas of Central Asia: Tien Shan and Pamir. We have received new knowledge on geological structure, deep structure and geodynamics of Pamir-Gissar-Alay zone which helps solving topical questions of tectonics and evolution of junction zone of Pamir and Tien Shan which remained debatable until now.
The major result of the research is the construction of a complex geological and geophysical model of Pamir and Gissar-Alay junction zone.
The independence factor of geologic and geodynamic development of Pamir and Gissar-Alay established on the base of multiple observations and facts, underlies the construction of this model.
The area of joining (interaction) of these two independent geodynamic provinces which geographically and tectonically corresponds to the system of intermountain troughs (Afgan-Tadjik, Alay, eastern part of Tarim) and mountain ranges (Zaalay, Petr Perviy), is an accommodation zone which serves as a damper of tectonic forces and stresses caused both by the pressure of Pamir and more southern elements of Alpine-Himalayan belt. It seems that this zone is geodynamically corresponded by the deep structure of intracontinental selfclosing subduction type, which is a special tectonic and geodynamic type of continental lithosphere structures.
The formation of modern architecture and infrastructure of Pamir-Gissar-Alay segment of the Earth’s crust and adjacent mountain areas is connected to the interference of two geodynamic settings: (1) global orogeny which covers large territories of Eurasia including Gissar-Alay and Pamir and which determined their similarities; (2) regional settings different for Pamir and for Gissar-Alay acting rather independently within Central Asian and Alpine-Himalayan active belts.
Another important result of this research is detection of specificities and differences of plastic flow structures’ forms in the Earth’s crust of Pamir and Gissar-Alay.
Within Gissar-Alay, Inner zone of the Northern Pamir, in the Central and Southern Pamir, the plastic flow was detected in the form of discrete subhorizontal layering of rock massifs, formation of disharmonic decollements and overthrust sheets complexes.
In Pamir, these processes cover the whole section from the Precambrian to the Cainozoic. They manifest both within the basement and the sedimentary cover, and are realized in the form of conglomeration of tectonic folds-covers.
In Gissar-Alay, the tectonic flow of rocks is concentrated mainly in the Palaeozoic basement rocks; in the younger sedimentations it is manifested only sporadically in the zones of concentrated deformation and viscous faults. The tectonic flow here is realized as a formation of large-scale basement folds and brittle-plastic “spreading” of the basement rocks in transverse and longitudinal directions. The bulk flow of basement rocks is put into effect by plastic deformation (which is detected in folds morphology, foliation, linearity, formation of layerwise viscous ruptures ect.), micro- and macro-fault deformation, bulk microcataclasis, dynamic recrystallization.