Russian Journal of Earth Sciences
Vol. 5, No. 4, August 2003
Geologic complexes of the southern marginal part of the Siberian
Craton
as indicators of the Neoproterozoic supercontinent evolution
E. V. Sklyarov, D. P. Gladkochub, A. M. Mazukabzov, T. V. Donskaya,
and A. M. Stanevich
Abstract
The aim of this paper is to discuss the Late Precambrian rock
complexes in the southern margin of the Siberian Craton, associated with the
extension. The analysis of the data available suggests two episodes of
intracontinental breakup which resulted in the opening of oceanic spaces
(1300-900 and 850-550 million years). The time sequence of "volcanogenic
terrigenous rocks of rifting origin
basic dike swarms
carbonate-terrigenous
rock sequences
ophiolites and island-arc rocks'' reflects the
consecutive change of geodynamic environments in the marginal part of the
craton. The stage of intracontinental rifting was replaced by the stage of
advanced rifting, which preceded the continental breakup and the formation of
the oceanic crust. Next followed two stages of oceanic crust evolution: the
passive stage (sedimentary complexes of the passive margins) and the active
stage (island arcs, backarc seas, and the like). Different versions are
discussed for the manifestation of extension processes in the southwestern and
southeastern segments of the Siberian Craton in connection with the breakup of
the Rodinia supercontinent.