SIBERIA IN RODINIA

It is generally assumed that the Siberian craton was a part of Proterozoic supercontinent Rodinia. However, its exact position in and the time of separation from the Rodinia are still under debate. Recent geological and paleomagnetic data from Siberia suggest the possible survival of some minor cratonic assemblage after the breakup of an unknown Paleoproterozoic supercontinent. This assemblage, which probably included Siberia and Laurentia, became the core of the Rodinia. We suppose the direct or indirect connection between the southern part of the Siberian craton and north Laurentia in this core. The absence of any traces of the large-scale Grenville-age collision in Siberia supports this model. The mantle-derived ultramafic complexes near the southern margin of Siberian craton were probably related to the mantle plume that later caused the breakup of Rodinia. During the early Neoproterozoic numerous dikes and sills were intruded into the eastern (about 1000 Ma) and southern (740-780 Ma) parts of the Siberian craton. The latter may be related to the Franklinian magmatic event in north Laurentia. At this stage the passive continental margin, marking the opening new oceanic basins were developed around its southern (Sayan-Baikal) margin. We suppose that the complete separation of Siberia from Rodinia happened at about 700 Ma.