Edge-Driven Convection

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The model of edge-driven convection (in German roughly plate-edge convection ) represents a possible explanation for the occurrence of tomographic anomalies. It is based on spatially relatively small convection cells in the upper mantle , where old continents ( cratons ) passively (essential younger) oceanic crust .

The cause of this convection is to be found on the one hand in the different temperatures of the upper mantle, which in turn is caused by the very different age of the lithosphere , on the other hand the nature of the mantle transition zone plays a role, which prevents material transport from deeper mantle regions from taking place. The upper mantle under old continents has usually already cooled down considerably, while the upper mantle under the oceanic lithosphere is hotter, which can lead to convection. These convection dynamics can be easily reconstructed with computer models . Since this is a phenomenon of plate tectonics that is ultimately caused by the lithosphere , it is also referred to as a "top-down", i.e. element that acts downwards from the top layer. This model can explain relatively simply the formation of certain geochemical patterns, such as those found in the Canary Islands , for example . It is disputed to what extent it is possible that such an element alone can explain a hotspot .

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