Concerning Paleogeographic Reconstructions and the State of the Geomagnetic Field at the Precambrian–Paleozoic Boundary: New Paleomagnetic Data for the Olenek Uplift (Siberian Craton)

• Published in: Doklady earth sciences 2022-10, Vol.506 (2), p.710-715
• Main Authors: Metelkin, D. V., Vinogradov, E. V., Shcherbakova, V. V., Vernikovsky, V. A., Zakharov, S. M., Nagovitsin, K. E.
• Format: Article
• Language: English
• Subjects: Analysis; Cratons; Dipole moments; Earth and Environmental Science; Earth Sciences; Embankments; Extreme values; Geology; Geomagnetic field; Geomagnetism; Magnetic anomalies; Magnetism; Magnetization; Palaeomagnetism; Paleogeography; Paleomagnetic studies; Paleomagnetism; Paleozoic; Platforms (geology); Precambrian; Rock intrusions; Rocks; Sills; Uplift
• ISSN: 1028-334X; 1531-8354
• DOI: 10.1134/S1028334X22600414

We report results of paleomagnetic studies of mafic dikes and sills from the Tas-Yuryakh magmatic complex on the Olenek uplift in the northeast of the Siberian platform. The paleomagnetic record in the rocks corresponds to an episode of anomalous state of the geomagnetic field that persisted from the Ediacaran period (~580 Ma and younger) to the end of the Fortunian age. Paleointensity measurements indicate an extremely low value of the virtual dipole moment during this time. This presumably caused a disruption of the normal Geocentric Axial Dipole model, so much so that the world magnetic anomalies made a substantial contribution. We propose that the Antarctic anomaly influenced the magnetization of the Siberian craton rocks during this period of very low dipole moment. The high latitudes corresponding to the observed paleopole do not correspond to the actual paleogeography of Siberia and can be used for paleoreconstructions only after adjusting for this anomaly. The true position of the Olenek uplift at the Precambrian–Paleozoic boundary was close to 30° S above the southeastern periphery of the African (Tuzo) mantle hot field.