Extensional basins of the former Soviet Union — structure, basin formation mechanisms and subsidence history

Abstract

We review the structure and evolution of a number of Riphean-Phanerozoic rifts and extensional basins within the territory of the former Soviet Union (FSU). Horst-and-graben formation in strong crustal and subcrustal lithosphere layers can explain the multi-trough character of rift systems observed in the Russian platform, the Vilyuy rift, the West Siberian rift system, the Pechora-Kolva rift system and the Laptev Sea rift. Many features in the evolution of these rifted basins are incompatible with predictions of classical stretching models. Basin subsidence often occurs in the absence of any noticeable stretching and over time scales much longer than predicted by models of thermal subsidence. Other observations include a time gap between rifting and the onset of post-rift basin subsidence of tens to hundreds Ma and a correlation in timing of subsidence phases of rifted basins and platforms with opening and closure events of adjacent ocean basins. These observations point to an important role for mechanisms such as eclogite formation within or beneath the lithosphere as well as intraplate compression and stress-induced lithospheric deflection.

Tectonic Models for the Evolution of Sedimentary Basins

“…However, in a number of basins, significant departures from the theoretical thermal subsidence curve are observed. These can in some cases be explained as effects of compressional intraplate stresses and related phase transformations (Cloetingh and Kooi, 1992a,b;Lobkovsky et al, 1996;Van Wees and Cloetingh, 1996). It appears that in many areas, the postrift evolution is characterized by initial rift-related subsidence, sometimes followed by accelerated subsidence of the central parts of an extensional sedimentary basin, simultaneously occurring with broad uplift in adjacent areas flanking the depocenter.…”

“…This process can be amplified in the cases of eclogite transformation of basaltic melts that were injected into the lithospheric mantle or that had accumulated at its base (Lobkovsky et al, 1996). However, it is uncertain whether large-scale eclogite formation can indeed occur at crustal thicknesses of 30-40 km (Carswell, 1990;Griffin et al, 1990).…”

Mechanical aspects of sedimentary basin formation: development of integrated models for lithospheric and surface processes

“…Another line of research has been the analysis by neural network technology (Van Balen and Cloetingh 1995) of the effect of stress-induced overpressures, linking backward analysis to predictions of forward modeling. The effects of intraplates stresses on the evolution of the basins on the Russian platform forms also a research topic carried out in the framework of the International Lithosphere Program (ILP) EUROPROBE project Lobkovsky et al 1996;Nikishin et al 1996).…”

Neoproterozoic metamorphism and deformation at the southeastern margin of the East European Craton, Uralides, Russia

“…In the southern Urals, the Kaltasy aulacogen is important in Riphean time. The sedimentation rate in the Kaltasy aulacogen changed in the late Middle Riphean to early Upper Riphean (Lobkovsky et al 1996;Maslov et al 1997). The first occurrence of nearshore and distinctive tidal-flat and shallowmarine deposits is known from top of the Zilmerdak sequence (~970 Ma, Maslov et al 1997).…”