Abstract
The data on the amplitude of variations in the direction and paleointensity of the geomagnetic field and the frequency of reversals throughout the last 50 Myr near the Paleozoic/Mesozoic and Mesozoic/Cenozoic boundaries, characterized by peaks of magmatic activity of Siberian and Deccan traps, and data on the amplitude of variations in the geomagnetic field direction relative to contemporary world magnetic anomalies are generalized. The boundaries of geological eras are not fixed in recorded paleointensity, polarity, reversal frequency, and variations in the geomagnetic field direction. Against the background of the “normal” field, nearly the same tendency of an increase in the amplitude of field direction variations is observed toward epicenters of contemporary lower mantle plumes; Greenland, Deccan, and Siberian superplumes; and world magnetic anomalies. This suggests a common origin of lower mantle plumes of various formation times, world magnetic anomalies, and the rise in the amplitude of geomagnetic field variations; i.e., all these phenomena are due to a local excitation in the upper part of the liquid core. Large plumes arise in intervals of the most significant changes in the paleointensity (drops or rises), while no correlation exists between the plume generation and the reversal frequency: times of plume formation correlate with the very diverse patterns of the frequency of reversals, from their total absence to maximum frequencies, implying that world magnetic anomalies, variations in the magnetic field direction and paleointensity, and plumes, on the one hand, and field reversals, on the other, have different sources. The time interval between magmatic activity of a plume at the Earth’s surface and its origination at the core-mantle boundary (the time of the plume rise toward the surface) amounts to 20–50 Myr in all cases considered. Different rise times are apparently associated with different paths of the plume rise, “delays” in the plume upward movement, and so on. The spread in “delay” times of each plume can be attributed to uncertainties in age determinations of paleomagnetic study objects and/or the natural remanent magnetization, but it is more probable that this is a result of the formation of a series of plumes (superplumes) in approximately the same region at the core-mantle boundary in the aforementioned time interval. Such an interpretation is supported by the existence of compact clusters of higher field direction amplitudes between 300 and 200 Ma that are possible regions of formation of world magnetic anomalies and plumes.
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References
A Geological Time Scale, Ed. by F. M. Gradstein et al. (Univ. Press, Cambridge, 2004).
Yu. S. Bretstein and A. V. Klimova, “The Paleomagnetism of Phanerozoic Terranes, Far East Russia: Comparison with North-China Plate Data (Review),” Russ. J. Earth Sci. 7(1) (2005); http://rjes.wdcb.ru.
V. Courtillot, A. Davaille, J. Besse, and J. Stock, “Three Distinct Types of Hotspots in Earth’s Mantle,” Earth Planet. Sci. Lett. 205, 295–308 (2003).
N. L. Dobretsov, A. G. Kirdyashkin, and A. A. Kirdyashkin, Deep Geodynamics (SO RAN, Novosibirsk, 2001) [in Russian].
R. E. Ernst and K. L. Buchan, “Recognizing Mantle Plumes in the Geological Record,” Annu. Rev. Earth Planet. Sci. 31, 469–523 (2003).
A. F. Grachev, “Mantle Plumes and Problems of Geodynamics,” Fiz. Zemli, No. 4, 3–37 (2000) [Izvestiya, Phys. Solid Earth 36, 263–294 (2000)].
E. L. Gurevich, C. Heunemann, V. Radko, et al., “Paleomagnetism and Magnetostratigraphy of the Permian-Triassic Northwest Central Siberian Trap Basalts,” Tectonophysics 2, 211–226 (2004).
A. V. Ivanov, S. V. Rasskazov, G. D. Feoktistov, et al., “40Ar/39Ar Dating of Usol’skii Sill in the South-Eastern Siberian Traps Large Igneous Province: Evidence for Long-Lived Magmatism,” Terr Nova, 1–6 (2005).
D. M. Jurdy, M. Stefanick, and C. R. Scottese, “Paleozoic Plate Dynamics,” J. Geophys. Res. 100, 17965–17975 (1995).
A. N. Khramov, G. I. Goncharov, R. A. Komissarova, et al., Paleomagnetology (Nedra, Leningrad, 1982) [in Russian].
R. L. Larson and P. Olson, “Mantle Plumes Control Magnetic Reversal Frequency,” Earth Planet. Sci. Lett. 107, 437–447 (1991).
M. W. McElhinny and P. L. McFadden, Paleomagnetism. Continents and Oceans (Academic, San Diego, 2000).
E. A. Molostovskii, M. A. Pevzner, D. M. Pechersky, et al., “Magnetostratigraphic Timescale of the Phanerozoic and the Geomagnetic Field Reversal Regime,” in Geomagnetic Research (Nauka, Moscow, 1976), Vol. 17, pp. 45–52 [in Russian].
D. M. Pechersky, “Latitude Dependence of the Total Amplitude of Paleovariations in the Geomagnetic Field Direction in the Neogaea,” Geomagn. Aeron. 36(5), 130–136 (1996).
D. M. Pechersky, “Some Properties of the Geomagnetic Field over 1700 Million Years,” Fiz. Zemli, No. 5, 3–20 (1997) [Izvestiya, Phys. Solid Earth 33, 341–357 (1997)].
D. M. Pechersky, “Neogeaen Paleomagnetism Constraints on the Processes at the Core and Surface of the Earth,” Russ. J. Earth Sci. No. 2, (1998); http://rjes.wdcb.ru.
D. M. Pechersky, “World Magnetic Anomalies and the Amplitude of Secular Variations in the Geomagnetic Field Direction,” Geomagn. Aeron. 40, 128–133 (2000).
D. M. Pechersky, “The Total Amplitude of Secular Variations, Global Magnetic Anomalies and Plumes,” Fiz. Zemli, No. 5, 85–91 (2001) [Izvestiya, Phys. Solid Earth 37, 429–435 (2001)].
D. M. Pechersky, “Geomagnetic Reversals, Plumes, and Changes in the Organic World in the Phanerozoic: Remarkable Coincidences,” Fiz. Zemli, No. 1, 53–56 (2003) [Izvestiya, Phys. Solid Earth 39, 48–51 (2003)].
D. M. Pechersky, “Geomagnetic Field near Paleozoic-Mesozoic Boundary and Siberian Superplume,” Russ. J. Earth Sci. 8(1), (2006); http://rjes.wdcb.ru.
D. M. Pechersky and A. N. Didenko, Paleo-Asian Ocean: Petromagnetic and Paleomagnetic Constraints on Its Lithosphere (OIFZ RAN, Moscow, 1995) [in Russian].
D. M. Pechersky and A. V. Garbuzenko, “The Mesozoic-Cenozoic Boundary: Paleomagnetic Characteristic,” Russ. J. Earth Sci. 7(2) (2005); http://rjes.wdcb.ru.
C. R. Scottese and W. S. McKerron, “Revised World Maps and Introduction,” in Paleozoic Paleogeography and Biogeography, Geological Society Memoir No. 12 (1990), pp. 1–21.
V. P. Shcherbakov, G. M. Solodovnikov, and N. K. Sycheva, “Variations in the Geomagnetic Dipole during the Past 400 Million Years (Volcanic Rocks),” Fiz. Zemli, No. 2, 26–33 (2002) [Izvestiya, Phys. Solid Earth 38, 113–119 (2002)].
M. A. Smethurst, A. N. Khramov, and T. H. Torsvik, “The Neoproterozoic and Palaeozoic Palaeomagnetic Data for the Siberian Platform: From Rodinia to Pangea,” Earth-Sci. Rev. 43, 1–24 (1998).
T. H. Torsvik and R. Van der Voo, “Refining Gondwana and Pangea Palaeogeography: Estimates of Phanerozoic Non-Dipole (Octupole) Fields,” Geophys. J. Int. 151, 771–794 (2002).
L. P. Zonenshain, M. I. Kuz’min, and M. V. Kononov, “Reconstructions of the Position of Continents in the Paleozoic and Mesozoic,” Geotektonika, No. 3, 16–27 (1987).
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Original Russian Text © D.M. Pechersky, 2007, published in Fizika Zemli, 2007, No. 10, pp. 49–59.
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Pechersky, D.M. The geomagnetic field at the Paleozoic/Mesozoic and Mesozoic/Cenozoic boundaries and lower mantle plumes. Izv., Phys. Solid Earth 43, 844–854 (2007). https://doi.org/10.1134/S1069351307100072
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DOI: https://doi.org/10.1134/S1069351307100072