PALEOMAGNETISM AND MAGNETOSTRATIGRAPHY OF PERMIAN-TRIASSIC REFERENCE SECTIONS IN THE CENTRAL RUSSIAN PLATE: ZHUKOV RAVINE, SLUKINO, AND OKSKIY SIYEZD
A.M. Fetisova1,2, V.K. Golubev3, R.V. Veselovskiy1,2, Yu.P. Balabanov4
1Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119234, Russia
2Shmidt Institute of the Physics of the Earth, Russian Academy of Sciences, ul. B. Gruzinskaya 10, Moscow, 123995, Russia
3A.A. Borissiak Paleontological Institute, Russian Academy of Sciences, ul. Profsoyuznaya 123, Moscow, 117647, Russia
4Kazan Federal University, ul. Kremlevskaya 18, Kazan, 420008, Russia
Keywords: Paleomagnetism, Permian, Triassic, magnetostratigraphy, Russian Plate
Abstract
The Permian-Triassic magnetostratigraphy of the central East European platform has been updated using evidence from the Zhukov Ravine, Slukino, and Okskiy Siyezd reference continental redbed sequences. The new data reveal five rather than four polarity subzones in magnetozone R3P, which thus can be ranked up to orthozone RnP. The upper Permian strata of the Zhukov Ravine and Okskiy Siyezd sections contain intervals of anomalous paleomagnetic directions similar to those revealed earlier in roughly coeval rocks from the Nedubrovo section in the Vologda region. The anomaly may be of regional extent and may correspond to quite a long (thousands of years) span of geomagnetic field stability near the Paleozoic-Mesozoic boundary, which fits the subequatorial dipole field in the first approximation. The paleomagnetic results were used to constrain the position of three new Permian-Triassic paleomagnetic poles of the East European platform, corrected for inclination shallowing: PLat = 54.8°, PLong = 173.6°, dp / dm = 2.6°/4.0° (Zhukov Ravine); PLat = 47.6°, PLong = 164.3°, dp / dm = 3.0°/4.8° (Slukino); PLat = 52.7°, PLong = 153.6°, dp / dm = 3.7°/5.4° (Okskiy Siyezd).
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