Attractor Structures of Riftogenesis as an Attribute of the Cenozoic Stage in Evolution of the Lithosphere within the Baikal Rift System

摘要

In accordance with the principle of actualism, the results of studying the modern geodynamics and tec-tonophysics of the Baikal rift system (BRS) have been applied for development and broadening of ideas about the Cenozoic Stage of the lithosphere in the region. Identification of three attractor structures of riftogenesis (ASR) has allowed the theory of modern geodynamics and tectonophysics of the BRS to be developed: the regional energy sources for geodynam-ical and seismic reconstructions have been included into the pattern, and their nature and effects have been described in the first approximation. Within the framework of the theory of dissipative dynamical systems of self-organization and nonlinear media, the ASRs have been considered as an attribute of Cenozoic geodynamics of the BRS lithosphere: they formed nonlinearity and instability of geodynamical and tec-tonophysical processes in this period of time. Three stages of volcanic activation of the BRS lithosphere are explained by sequential origination and development of three ASRs: firstly, in the South Baikal Depression (Late Cretaceous-Paleocene), then in the Khubsugul Depression (Eocene-Oligocene), and finally in the Muya Depression (post-Oligocene). The start of the Cenozoic riftogenic stage of the Baikal Depression about 70 Ma BP is explained by appearance of the ASR is the South Baikal Depression. Two stages of rifting, an increase in the rate of rift processes in the BRS, and propagation of riftogenesis southwestwards and northeastwards from the South Baikal Depression are attributed to the appearance and gradual two-lateral evolution of the ASRs in the Khubsugul (southwestern flank) and Muya (northeastern flank) depressions.