Geochemistry of U and Th and its Influence on the Origin and Evolution of the Crust of Earth and the Biological Evolution - Physics > GeophysicsReport as inadecuate




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Abstract: We have investigated the migration behaviors of uranium U and thorium Thin Earth and other terrestrial planets. Theoretical models of U and Thmigration have been proposed. These models suggest that the unique features ofEarth are closely connected with its unique U and Th migration models anddistribution patterns. In the Earth, U and Th can combine with oxidativevolatile components and water, migrate up to the asthenosphere position to forman enrichment zone EZ of U and Th first, and then migrate up further to thecrusts through magmatism and metamorphism. We emphasize that the formation ofan EZ of U, Th and other heat-producing elements is a prerequisite for theformation of a plate tectonic system. The heat-producing elements, currentlymainly U and Th, in the EZ are also the energy sources that drive the formationand evolution of the crust of Earth and create special granitic continentalcrusts. In other terrestrial planets, including Mercury, Venus, and Mars, an EZcan not be formed because of a lack of oxidative volatile components and water.For this reason, a plate tectonic system can not been developed in theseplanets. We also emphasize the influence of U and Th in EZ on the developmentand evolution of life on Earth. We propose that since the Earth and planetswere born in a united solar system, there should be some common mechanisms tocreate the similarities and differences between them. We have tried to developan integrated view to explain some problems in the tectonics of Earth andevolution, bio-evolution, and planetary dynamics through U and Th geochemistry.We believe that a comprehensive exploration on energy sources and theirevolution is a good way to build bridges between different disciplines ofscience in order to better understand the Earth and planets.



Author: Xuezhao Bao, Ali Zhang

Source: https://arxiv.org/







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