PALEOMAGNETISM, MICROPLATES AND SIBERIAN PLATE CONSOLIDATION

Abstract

Abstract Paleomagnetic research in the Siberian area provides new data to derive models of relative horizontal movements and the process of amalgamation or consolidation of the Siberian plate. Comparison of the Apparent Polar Wander (APW) curves for different regions of Siberia show that there were several stages of plate consolidation, the most important of which belonged to Baikalian time (c. 520–800 Ma). The consolidation was complicated by rifting processes. There were six megaterrains in pre-Vendian times, which underwent differential horizontal displacements. The joining of the Altai-Sayan fold area and the North-East microplates and fold belts to the Siberian plate, and the separation of the Taimyr peninsula, were the main post-Baikalian events. The most complete geologic sections were studied in conjunction with radiometric age dating and related to the geochronological Precambrian time scale of the USSR. This has led to the discovery of a stratigraphic polarity bias in the early Riphean-Vendian interval. There were five polarity stages in this interval 200–240 Ma each.