Paleomagnetism of the phanerozoic sequences of the central part of the Central Asian fold belt

Abstract

The article summarizes paleomagnetic data for Tuva, Mongolia and Eastern China, which showed that in the central part of the Central Asian fold belt, areas with different paleomagnetic characteristics are distinguished, these are areas located north of the Mongol-Okhotsk mobile belt, the western and eastern parts of the South Mongolia and Eastern China. The areas located north of the Mongol-Okhotsk mobile belt were part of the structure of the Siberian continent from the Ordovician and experienced movement similar to the Siberian continent. The regions of the western part of Southern Mongolia have been part of the structure of the Siberian continent since the late Carboniferous. The geological complexes of the eastern part of Southern Mongolia and the blocks of Eastern China in the Middle Paleozoic and Early Mesozoic were located in a latitudinal interval close to the North China block and experienced similar latitudinal movements and similar rotations. The large difference between the paleolatitudes of coeval strata in western and eastern Mongolia and Eastern China south of the Mongol-Okhotsk mobile belt suggests the existence of a tectonic boundary that separated blocks formed at paleolatitudes along the 107E meridian, close to Siberia and Northern China. To the west of the 107° longitude meridian, the paleolatitudes of formation of the Late Carboniferous–Permian strata are close to the paleolatitudes of Siberia, and to the east of the meridian — to the paleolatitudes of Northern China. The width of the Mongol-Okhotsk Ocean in the late Paleozoic–early Mesozoic was 30°–40° latitude (~3000–4000 km). The southern limit of the Mongol-Okhotsk Ocean was segmented and consisted of terranes of various genesis and structure. The closure of segments of the Mongol-Okhotsk Ocean occurred as a result of the collision of terranes with the Siberian continent during the period from the Late Carboniferous (in the west) to the Jurassic (in the east).