Continental Evolution and Archaeo-Sea-Levels
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The Archaean geodynamic regime is related to the process of mantle diapirism and creation of oceanic crust and lithosphere. Thick Archaean basaltic crust, by internal instability and convection and repeated melting could produce continental crust, which accumulated into proto-continents.
Large vertical displacements of the Archaean continental crust can be explained in terms of specific isostatic conditions and intensive erosion and deposition due to a falling relative sealevel. Accretion by underplating of new crust from the mantle is accomplished by renewed partial melting of the partially depleted mantle root.
Given that Archaean cratons and their tectosphere have stabilized shortly after their formation, the proposed geodynamic process must have taken place in a relatively short time interval. Corresponding relative sealevel changes amount to a magnitude of the order of kilometers.
KeywordsOceanic Crust Plate Tectonic Oceanic Lithosphere Basalt Layer Mantle Temperature
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