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Spectrum of Quaziperiodic Variations in Paleomagnetic Activity in the Phanerozoicстатья
- Авторы: Kurazhkovskii А.Yu, Kurazhkovskaya N.А., Klain B.I.
- Журнал: Geologiya i Geofizika
- Том: 63
- Номер: 11
- Год издания: 2022
- Первая страница: 1261
- Последняя страница: 1269
- Аннотация: Detection of common quasiperiodicities in the paleointensity behavior and lengths of polarity intervals of the Earth’s magneticfield was carried out. The paleointensity data were analyzed in the 170 Ma–present day interval. Behavior of the lengths of geomagneticpolarity intervals was investigated within the interval spanning the entire Phanerozoic (540 Ma–present age). It was found that thespectrum of the main paleointensity variations and polarity interval lengths is discrete and includes quasiperiodic variations with characteristictimes of 15, 8, 5, and 3 Ma. The characteristic times of these quasiperiodic variations in the geomagnetic field at the beginning and endof the Phanerozoic differed not more than 10%. The spectral density of quasiperiodic changes in the geomagnetic field changed cyclicallyover geological time. The connection between the behavior of the amplitudes of paleointensity variations, the lengths of geomagnetic polarityintervals, and their spectral density is shown. The spectral density of quasiperiodic paleointensity variations (geomagnetic activity) wasrelatively high in the 150–40 Ma interval (Cretaceous–early Paleogene). At this time, the amplitudes of paleointensity variations and thelengths of geomagnetic polarity intervals increased. Within the intervals spanning 170–150 Ma and 30 Ma–present age, the quasiperiodicvariations of paleointensity were barely expressed against its background noise variations, while the amplitudes of paleointensity variationsand the lengths of polarity intervals were decreasing. Alternations of the time intervals in which paleointensity variations acquired either aquasiperiodic or noise character took place during the evolution of the geomagnetic field.
- Добавил в систему: Куражковский Александр Юрьевич