Paleomagnetism of the Permian-Triassic traps from the Kuznetsk Basin, Southern Siberia

In this paper we generalize the data obtained for the Kuznetsk Basin traps studied over many years. A rich collection of samples from the Permian and Triassic igneous/sedimentary succession of the Kuznetsk Basin was analyzed. As a result, directions of characteristic remanent magnetization have been established (D-s = 227.1, I-s = -64.3, alpha(95) = 2.8). Also, the paleomagnetic pole has been located accurately enough to be used in paleotectonic reconstructions. The Permian-Triassic age of the characteristic component of magnetization has been confirmed by fold and baked-contact tests. Comparative analysis of the magnetic zoning record in the sections of traps of the Kuznetsk Basin, northern Siberian Platform and West Siberian Plate shows that the processes of intraplate magmatism were mutually related in these areas about the time of the Permian-Triassic transition. Systematization of the obtained and available paleomagnetic data shows that the trap magmatism in the Kuznetsk Basin, as compared with the rest of Siberia, was an extremely short-term event. The entire section corresponds to the initial stage of the intraplate magmatic activity in the Siberian region, with their formation lasting no more than 1 Myr. The position of the calculated paleomagnetic pole (PLat = 60.0, PLong = 172.7, alpha(95) = 4.0) and the orientation of the Permo-Triassic latitudes of the Kuznetsk Basin have a considerable angular deviation from those of the Siberian Platform (PLat = 49.0, PLong = 151.6, alpha(95) = 5.0). The angular distance makes about 24 degrees of the large circle and is due to intraplate strike-slip displacements. The nature of the strike-slip movements is interpreted in terms of plume tectonics and is governed by the clockwise rotation of the Siberian part of the Eurasian continent relative to the European part. Thus, the formation of the Permian-Triassic volcanotectonic structures of the Kuznetsk Basin followed the "pull-apart" scheme.