Paleomagnetism of the Sette-Daban Meso-Neoproterozoic magmatic complex of the southeastern margin of the Siberian platform

Abstract

The interval of ~ 1000 - ~ 900 Ma is one of the key ones in the history of the evolution of the Siberian Platform. At this time, the formation of the neoproterozoic supercontinent Rodinia took place, which undoubtedly found its reflection in the geological annals of Siberia. A reflection of the kinematics of the Siberian platform is its apparent pole wander path (APWP), the development of which will help to clarify the geodynamic in which the platform was at the beginning of the Neoproterozoic. However, not many objects of this age are known within the Siberian Platform, suitable for performing paleomagnetic determinations. The consequence of this is a very limited number of existing reliable poles, obtained either from sedimentary rocks with very imprecise age limits, or from rocks of the Yenisei Ridge and Taimyr with an ambiguous structural position. This paper presents the results of paleomagnetic studies of the Proterozoic igneous rocks of the Sette-Daban complex of the southern Verkhoyansk region, the formation of which took place ~ 1000-970 Ma ago. Detailed thermal magnetic cleaning made it possible to reveal the high-temperature (HT) characteristic component in a significant part of the samples. It has maximum unblocking temperatures of about 580 ° C, lying in the region of the Curie point of magnetite. The average direction of the characteristic component for the sills sampled in the valley of the Yudoma, coincides with the direction obtained earlier on the same bodies. The calculated paleomagnetic pole for the intrusive bodies of the Sette-Daban magmatic complex (Plat = 5.8 °, Plong = 182.9 °, dp / dm = 9.0 ° / 14.4 °) confirms and refines the previously obtained pole for the rocks of this complex, and also indicates that Siberia in the range of ~ 970-1000 Ma was located in the northern hemisphere in tropical latitudes (~ 26 ° N). The analysis of the available geochronological and geochemical data, coupled with new paleomagnetic data, made it possible to clarify the age of the Sette-Daban magmatic event and limit it within ~ 970-1000 Ma.