TY - JOUR

T1 - PALEOMAGNETISM OF THE VOROGOVKA GROUP: SUBSTANTIATING THE VENDIAN GEOMAGNETIC PHENOMENON (Yenisei Ridge)

AU - Vinogradov, E. V.

AU - Metelkin, D. V.

AU - Letnikova, E. F.

AU - Kosareva, L. R.

AU - Abashev, V. V.

AU - Vishnevskaya, I. A.

N1 - This study was funded by grant no. 24-17-00057 from the Russian Science Foundation (processing results of rock-magnetic and paleomagnetic experiments). The research topic is in accordance with programs of fundamental research of the RAS: FWZZ-2022-0001 (IPGG SB RAS, paleotectonic reconstructions based on paleomagnetic data), FWZN-2022-0036 (IGM SB RAS, provenance study from detrital zircon), and the state assignment of GEOKHI RAS (interpretation of Sr isotope data in carbonate rocks); as well as of the Ministry of science and higher education of Russia, program FSUS-2025-0008 (NSU, analysis of the evolution and modeling of the structure of the geomagnetic field at the Precambrian\u2013 Paleozoic boundary). We are grateful to the staff of the Interdisciplinary Center for Analytical Microscopy of Kazan Federal University for performing the SEM investigations.

PY - 2025/4/1

Y1 - 2025/4/1

N2 - We report new paleomagnetic data for the carbonate-terrigenous section of the Vorogovka Group at its type locality along the Vorogovka River in northwestern Yenisei Ridge. The data is synthesized with existing information on the age of the rocks, including our new determinations using detrital zircons from sandstones and Sr chemostratigraphy for carbonate rocks from all three stratigraphic units of the group: Severnaya Rechka, Mutnina, and Sukhaya Rechka formations. These findings definitively indicate a younger age for the strata, in the range of 580–535 Ma, with a relatively rapid rate of sedimentation, contrary to previous estimates. The anomalous paleomagnetic record typical for the Vendian (Ediacaran)–early Cambrian period and the proximity of the paleopoles established for Siberia both suggest that the rocks formed over an even shorter interval, between 580 Ma and 560 Ma. The data shows that the paleomagnetic record of the Vorogovka Group contains, in addition to a viscous component, a metachronous magnetization, presumably of Cambrian age, and two coeval components of primary origin. The coexistence of these components in a single section does not correspond to actualistic ideas about the prevailing geocentric axial dipole geometry of Earth’s magnetic field and is the subject of a long-standing debate. Our analysis of the new data and its comparison with existing paleomagnetic records for Siberia provided new insights into the interpretation of the Vendian geomagnetic phenomenon within an original hypothesis. According to this model, the second magnetization component in the Vendian–lower Cambrian section is explained by a sharp decline in the main dipole component of the geomagnetic field to values comparable to the intensity of the global magnetic anomalies. This phenomenon distorted the conventional paleomagnetic record to varying degrees, and during periods of ultra-low dipole strength, it sometimes entirely replaced the usual record. Accordingly, these paleomagnetic vectors no longer oriented toward the magnetic pole but instead aligned with the nearest magnetic anomaly. This hypothesis is used to interpret not only the paleomagnetic vectors observed in the Vorogovka Group but also the entire set of paleomagnetic data for the Vendian–early Cambrian formations of Siberia.

AB - We report new paleomagnetic data for the carbonate-terrigenous section of the Vorogovka Group at its type locality along the Vorogovka River in northwestern Yenisei Ridge. The data is synthesized with existing information on the age of the rocks, including our new determinations using detrital zircons from sandstones and Sr chemostratigraphy for carbonate rocks from all three stratigraphic units of the group: Severnaya Rechka, Mutnina, and Sukhaya Rechka formations. These findings definitively indicate a younger age for the strata, in the range of 580–535 Ma, with a relatively rapid rate of sedimentation, contrary to previous estimates. The anomalous paleomagnetic record typical for the Vendian (Ediacaran)–early Cambrian period and the proximity of the paleopoles established for Siberia both suggest that the rocks formed over an even shorter interval, between 580 Ma and 560 Ma. The data shows that the paleomagnetic record of the Vorogovka Group contains, in addition to a viscous component, a metachronous magnetization, presumably of Cambrian age, and two coeval components of primary origin. The coexistence of these components in a single section does not correspond to actualistic ideas about the prevailing geocentric axial dipole geometry of Earth’s magnetic field and is the subject of a long-standing debate. Our analysis of the new data and its comparison with existing paleomagnetic records for Siberia provided new insights into the interpretation of the Vendian geomagnetic phenomenon within an original hypothesis. According to this model, the second magnetization component in the Vendian–lower Cambrian section is explained by a sharp decline in the main dipole component of the geomagnetic field to values comparable to the intensity of the global magnetic anomalies. This phenomenon distorted the conventional paleomagnetic record to varying degrees, and during periods of ultra-low dipole strength, it sometimes entirely replaced the usual record. Accordingly, these paleomagnetic vectors no longer oriented toward the magnetic pole but instead aligned with the nearest magnetic anomaly. This hypothesis is used to interpret not only the paleomagnetic vectors observed in the Vorogovka Group but also the entire set of paleomagnetic data for the Vendian–early Cambrian formations of Siberia.

KW - Ediacaran

KW - Siberian Craton

KW - Vorogovka Group

KW - Yenisei Ridge

KW - detrital zircons

KW - paleogeography

KW - paleomagnetism

UR - https://www.mendeley.com/catalogue/b833db6f-6b44-378d-99b3-c7778ff5bd02/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-105001961583&origin=inward&txGid=bbcb1d94ee1042941f164d1f86db0ac3

U2 - 10.2113/RGG20244830

DO - 10.2113/RGG20244830

M3 - Article

VL - 66

SP - 403

EP - 423

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 4

ER -