GEOLOGICAL COMPLEXES IN THE MARGIN OF THE SIBERIAN CRATON AS INDICATORS OF THE EVOLUTION OF A NEOPROTEROZOIC SUPERCONTINENT

Abstract

This paper describes the Late Precambrian geologic complexes from the southern margin of the Siberian Craton, associated with the extension epochs. Analysis of the data available suggests that there were two episodes of intracontinental breakup, which resulted in the opening of the ocean (1300-900 and 850-550 million years ago). The time sequence of the "rift-related volcanic rocks and terrigenous deposits <img src="/get_item_image.asp?id=21531049&img=latex131.gif" align=absmiddle border=0> basic dike swarms <img src="/get_item_image.asp?id=21531049&img=latex131.gif" align=absmiddle border=0> carbonate-terrigenous rocks <img src="/get_item_image.asp?id=21531049&img=latex131.gif" align=absmiddle border=0> ophiolites and island-arc rocks reflects the successive change of geodynamic environments in the marginal part of the craton. The stage of intracontinental rifting was superseded by the stage of advanced rifting which preceded the continent break and the formation of oceanic crust. This period was followed by two phases of oceanic evolution: a passive phase (sedimentary rocks of the passive margins) and an active phase (island arcs, backarc seas, and the like). Several different versions are offered and discussed for the extension processes in the southwestern and southeastern parts of the Siberian Craton is association with the breakup of the Rodinia Continent.