Re-deciphering the tectonic jigsaw puzzle of northern Eurasia

Northern Eurasia consists of the East European, Siberian, North China, and Alai-Tarim cratons, fragments of the supercontinent Rodinia, and the orogens of the Baikalides, Timanides, Uralides, Altaids, and Mongolides. These can be collectively classified as the Central Asian supercollage. The Baikalides and Timanides host Meso- and Neoproterozoic magmatic arc terranes that were sutured with the adjacent East European and Siberian cratons in the end of the Neoproterozoic. The Paleozoic part of the supercollage consists of three almost synchronous and subparallel Neoproterosoic to Paleozoic magmatic arc and turbidite superterranes, as well as overlap assemblages, bent into the world's largest oroclines. Analysis of their structural pattern, supported by paleontological, lithological, and paleomagnetic data, indicates that these superterranes might have been produced via formation of arc-backarc systems at the margin of combined North China, East European and Siberian cratons and then deformed during Paleozoic: westward-directed strike-slip translation between the clockwise rotating Siberian and eastward moving North China cratons. It is proposed that this development took place against the respective breakup of the above-mentioned cratons from the northern and southern margins of Eastern Europe in the Neoproterozoic, initially as a group of cratons called Nena, which reassembled in late Paleozoic to early Mesozoic times into Laurasia, part of the new supercontinent Pangea. In Mesozoic-Cenozoic times, the subduction-related continental growth of northern Eurasia continued in the Nipponide, Kamchatka and Kolyma-Alaska orogenic collages of the northern Circum-Pacific, which consist of Paleozoic to Cenozoic turbidite to island arc superterranes and overlap assemblages, generally younging towards the Pacific oceanic plate and also severely oroclinally bent. It is proposed that terranes of the Kolyma-Alaska and Kamchatka collages were translated westward, dextrally relative to Siberia, whereas Nipponides were translated northward, relative to North China, similarly to the better constrained Mesozoic-Cenozoic reconstructions of southeastern Asia. The two groups of collages started to collide along the Mongol-Okhotsk suture zone in the south of the Siberian craton in the end of the Mesozoic and then continued to collide along the presently active plate boundary at the island of Sakhalin. The proposed scenario suggests similarities in Paleozoic evolution of the Central Asian and Mesozoic-Cenozoic evolution of the northern Circum-Pacific supercollages, both possibly formed in response to westward subduction and related strike-slip translation of the (Paleo)-Pacific oceanic plates. The individual superterranes might have been consequently translated for as much as 40006000 km and oroclinally bent during such translation or/and rotation of the adjacent cratons. (c) 2007 Elsevier Ltd. All rights reserved.