Paleoproterozoic Evolution of Mafic–Ultramafic Magmatism of the Kun-Manie Ore Field (Aldan-Stanovoy Shield): Evidence from Paleomagnetic Data

Resumo

The results of petromagnetic and paleomagnetic studies of the Late Paleoproterozoic nickeliferous mafic–ultramafic rocks of the Kun-Manie ore field located in the southeast of the Aldan–Stanovoy Shield are reported. Our research is focused on intrusions of two morphogenetic types: the Black Giant and Meridional dykes and Kubuk and Iken sills. The petromagnetic data suggest a correlation between the attitude of the studied intrusions and the orientation of the axes of the anisotropy ellipsoid of the initial magnetic susceptibility, which can be used during geological survey, prospecting, and evaluation. Based on the data of our paleomagnetic studies, two stages in the Paleoproterozoic igneous activity were distinguished: the first is related to intrusion of sills, the second, to intrusion of dykes. The orientations of the characteristic component of magnetization isolated in all intrusive bodies of the complex were used to calculate the coordinates of the paleomagnetic pole. The position of the pole corrected for the opening of the Vilyui Rift in the Paleozoic is close to the range between 1700 and 1720 Ma of the apparent polar wander path for the Siberian Craton, which is in a good agreement with the geochronological data available.