A.Yu. Kazansky

The Mesozoic Apparent Polar Wander Path for the Siberian Domain of the Eurasian Plate

Comparison of the apparent polar wander paths (APWP) is one of the most important tasks in recent paleomagnetic study. The reliability of such trajectories is largely determined by the quality and quantity of paleomagnetic data used for their construction and uniformity of distribution of these data along the APWP. Approximately 400 paleomagnetic determinations largely characterizing the Paleozoic are now available for East Siberia. The basic features of the present-day structure of northern Eurasia were formed by the end of the Paleozoic. This fact served as a basis for construction of the so-called synthetic APWP for the Eurasian continent, according to which the latter is considered as a single rigid block in the Mesozoic‐Cenozoic [1, 2]. Though paradoxical, Mesozoic strata of Siberia, except for the Lower Triassic, are insufficiently studied by the paleomagnetic method. The paleomagnetic study of Mesozoic rocks in Siberia were largely aimed at solution of stratigraphic problems, which do not need high accuracy in determination of paleomagnetic poles. Despite their reliability, such data are unsuitable for solution of tectonic tasks. The main weakness of available determinations is related to the lack of paleomagnetic tests and wide age ranges (sometimes >50 (!) Ma) obtained for paleomagnetic poles. Therefore, paleomagnetic data on Europe and China [1, 2] were used to calculate the latitudinal position and spatial orientation of the Siberian tectonic domain of the Eurasian Plate in the Mesozoic‐Early Cenozoic. At the same time, the analysis of the geological structure and paleomagnetic data available for Siberia, East Europe, and Central Asia indicates that such constructions are inconsistent

Rotation parameters of the Siberian domain and its eastern surrounding structures during different geological epochs

The motion of lithospheric blocks was analyzed in the junction zone between the Eurasian Plate and its surrounding structures. Its present-day stage was considered using GPS and seismologic data. Models of the movement of a rigid plate are considered for Eurasia. A model of Eurasia (northern part of Asia) was used to determine the rotation parameters of its southern periphery (Amur Plate) based on GPS data for the Far East (Sikhote Alin profile), and Transbaikal regions are shown as an example. A model of the Amur Plate was used to illustrate the behavior of the extension zone on its western boundary represented by the Lake Baikal depression during the Kultuk earthquake (M = 6.3, August, 27, 2008). Paleomagnetic data made it possible to determine the rotation pole of the Siberian Craton relative to its surrounding folded structures during the Mesozoic and to estimate its kinematic parameters. The permanent position of the rotation pole in the relative coordinate system since the terminal Paleozoic until the Recent indicates a constant rotation velocity of the Siberian domain within the Eurasian Plate structure.