Contribution of the cyclical meridional component of continental drift to the evolution of the supercontinents of the Earth: global palaeomagnetic geodynamicsтезисы доклада

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1. Полный текст Goncharov_Lubnina_Raznitsin_Barkin_-_2013.doc 26,0 КБ 23 мая 2013 [Goncharov_MA]

[1] Contribution of the cyclical meridional component of continental drift to the evolution of the supercontinents of the earth: global palaeomagnetic geodynamics / M. Goncharov, N. Lubnina, Y. Raznitsin, Y. Barkin // Rodinia 2013: Supercontinental Cycles and Geodynamics. Eds.: Veselovskiy R., Lubnina N. — PERO Press Moscow, 2013. — P. 33–33. ISBN 978-5-91940-611-2. State of the problem. Since the middle of the last century, systematic building up of a database on reconstruction of the locations of continents and their fragments in the geological past takes place. An example is the revealing East European craton drift from Neoarchean to Palaeozoic. New recently developed directions of research can be called "global palaeomagnetic geodynamics”. Its subject is the mechanism of creation and break-up of supercontinents and the nature of supercontinental cyclicity. Brief history and various hypotheses on this subject are contained in a recent (2009) review publication of Z.X. Li. and S. Zhong. The authors' hypothesis of supercontinent-superplume coupling and true polar wander (TPW) seems realistic. However, the hypothesis seems to be correct concerning the cause of 2 cellular convection, but the genesis of 1-cellular convection remains mysterious. This cell is organized in such a way that convection causes the continents to accumulate in high latitudes that is energy-inefficient and leads, in its turn, to the TPW. This means that for accumulation of continental masses in the polar region some extraneous factor is required. Furthermore, the origin of superplume under supercontinent, when the latter is in high latitudes, is doubtful. Model of the authors. During the break-up of a supercontinent located at low latitudes (such as Columbia, Rodinia, Pangaea), its fragments do not only "run up" centrifugally (under the influence of the superplume below) but also move to high latitudes (under the influence of directed to one pole drift of the Earth’s core), forming a supercontinent. Then, influenced by the TPW, this continental mass drifts to low latitudes, forming the next supercontinent at the equatorial area. The center of this supercontinent is removed to the East at 90o in relation to the center of the previous equatorial supercontinent. During the subsequent break-up of the latter which designate the beginning of the new supercontinental cycle, its fragments drift to high latitudes of the other pole of the Earth. The superplume under a supercontinent, as well as the 2-level convection with another – antipodal – superplume, arise when, under the influence of TPW, supercontinent proved to be at the equatorial zone, which constantly runs “hot belt”. Conclusions. All the three main processes: (1) forming the superplume under an equatorial supercontinent with the subsequent its break-up, (2) accumulation of continental masses in one of the polar regions of the Earth under the influence of the meridional drift of the Earth’s core, and (3) the formation of a supercontinent at the equatorial zone influenced by TPW, are tied to the Earth's axis of rotation. Accordingly, this binding is characterized by both the 1-cell and 2 cell convection in the Earth's mantle, which function under the influence of various factors and interfere with each other, defining the global picture of location of continents on the Earth's surface.

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