Where was Siberia in Mid Paleozoic? New paleomagnetic evidence

New reliable paleomagnetic data from the Siberian Platform help in deciphering its paleogeography during ~450-400 Ma.Geochronology of late Devonian mafic sills provides time constraints for tectonic deformation along the southern margin and thus a minimum age for the regional magnetic overprint.From a late Ordovician-Silurian sedimentary section of the Nyuya syncline in the southern part of the Siberian platform with the Devonian sills hosted nearby in early Paleozoic sediments, pre-folding presumably primary magnetization was isolated from the sediments during stepwise thermal cleaning.Another component recorded in both the Silurian and Ordovician samples is pre-folding.This component was probably formed during a regional remagnetization event, which took place in post-early Silurian time.Putting this secondary component into a framework with available Paleozoic data and geochronology further constrains its age to be early Devonian.The isolated components yield new late Ordovician, early Silurian and early-middle Devonian paleomagnetic poles.The revised middle Paleozoic segment of the apparent polar wander path (APWP) for the Siberian Platform provides new paleogeographic constraints.Our data suggest that in late Ordovician the platform was situated in equatorial latitudes and was rotated 180 deg. with respect to its present position.During middle-late Ordovician time the platform did not experience any noticeable latitudinal drift.It started drifting to the north in the late Ordovician, and by the late Silurian it had traveled ~1500 km northward and had rotated ~30 deg. CCW.During late Silurian time the platform continued northward drift and counterclockwise rotation, and by the early Devonian it had drifted ~1100 km northward and rotated 10 deg. CCW.After that, the rotation of the platform changed to clockwise, and by the late Devonian had drifted another 1500 kilometers to the north and had rotated ~60 deg. CW.We evaluated paleomagnetically viable positions from 450-400 Ma of the three largest Laurasian cratons,Siberia,Baltica and Laurentia,based on the new data and previously published APW paths.Contrary to several published reconstructions,the Siberian platform could not have been situated to the north of the Caledonian suture in mid-Silurian time,but was probably located either at the eastern or the western side of Laurussia.The new data are compatible with an early Devonian position of Siberia similar to the modern Eurasian configuration.They also support the post- early or middle Devonian relative rotation between the Aldan and Angara blocks of the Siberian platform.