International Geologiical Congress - Oslo 2008

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ASI-02 Geology and mineral resources of Northern and Central Eurasia

 

Tectonics of northern Eurasia

 

Alexander Yakubchuk, CERCAMS, Natural History Museum/Geological Institute, Moscow (United Kingdom)
 

 

Northern Eurasia consists of several Archean to Mesoproterozoic cratons (East European, Arctic, Hyperborean, Siberian, North China, Alai-Tarim), which can be reconstructed into a single cratonic mass within the supercontinent Rodinia so that Siberia would occur between North America and Australia. The penetration of the oceanic spreading centers into Rodinia might have taken place between Siberia and Australia. The post-720 Ma global kinematic history can be then viewed as a consequence of the drift of these two cratons towards each other in the opposite hemisphere, both being responsible for creation of the Central Asian supercollage in the heart of Northern Eurasia.

The Central Asian supercollage consists of Neoproterozoic (Baikalides and Timanides) and Paleozoic (Uralides, Altaids, and Mongolides) orogens. In the east, the supercollage and adjacent cratons are framed by Mesozoic-Cenozoic Circum-Pacific supercollage, consisting of Kolyma-Alaska, Nipponide, and Kamchatka orogens. Each of them hosts cratonic terranes, as well as oroclinally bent magmatic arc and turbidite terranes and overlap assemblages, generally younging towards the Pacific oceanic plate.

The tectonics of the Baikalides and Timanides is relatively simple, but the timing of deformations is currently under considerable review. In the Uralides, Altaids, and Mongolides, the three, almost synchronous Vendian to Paleozoic magmatic arc and turbidite superterranes and overlap assemblages, might have originally emerged as a single magmatic arc, and then split via intra-arc spreading events. On the basis of paleomagnetic, kinematic, and paleontological data, I propose that their present giant S-shaped oroclinal pattern might have been produced against the background drift during 400 Ma of Paleozoic times of the Siberian craton from North America towards Eastern Europe for about 5,000 km and eastward drift of the North China and Alai-Tarim(?) cratons for 6,000 km relative to Eastern Europe, the latter being indirectly pushed by Australia.

The Circum-Pacific supercollage simply inherited the continental growth from Central Asia. Kolyma-Alaska collage was amalgamated and oroclinally bent between the Hyperborean and Siberian cratons, whereas Kamchatka and Nipponide collages were oroclinally bent during their translation towards each other on the opposite flanks of the westward subducting Pacific oceanic plate.

 

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