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Two concepts, endogenous regimes and plate tectonics are compared for regions of West Siberia, Europe and the North Atlantic. Endogenous regimes concept (Beloussov, 1990) are based on the assumption of permanent vertical relationships or long-term interactions between the crust and upper mantle control crustal evolution. Significant horizontal movements of the lithosphere, as required by global plate tectonics, would destroy these crust-mantle interactions and that is why these two concepts contradict each other. The endogenous regime concept assumed also the formation of the oceans by subsidence of large parts of the continents and by crustal transformation into oceanic crust. Certain regular features of the crust and upper mantle observed in the study regions support these assumptions and are difficult to explain in terms of conventional plate tectonics. Seismic studies show regularities in crustal structure changes from inner parts of the Eurasia continent to its margins and to the oceans. In the inner parts thick continental crust is observed. In deep sedimentary basins its thickness decreases due to wedging out of the upper crust (“granitic”) layer. In West Europe the crust is also thinner but because of high velocity lower crust wedging out. The thinning of the crust continues and become more and more pronounced in the ocean, where continental crust transforms into suboceanic and then into oceanic crust. This crustal transformation correlates with the tectono-magmatic activation regime and with areas of high heat flow, lower mantle velocities and with the geoid positive anomaly. The latter means that there is higher heat flow from at least the transition zone between the upper and lower mantle and transforms the continental crust in areas of West Europe and the North Atlantic. The origin of the North Atlantic ocean by subsidence is confirmed by deep drilling data which show shallow water sediments covering the whole ocean region and it suggests the existence of continental crust at the first stage of ocean formation. Sudden subsidence of large areas is documented by drilling and seismic studies not only in the North Atlantic, but in the Arctic ocean and adjacent continental margins as well. No significant stretching was observed to accompany this subsidence. |
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