Planetary Felsic Crust Formation at Shallow Depth
Abstract
Current theories suggest that on Earth and, possibly, on other terrestrial planets early in their history, the first continental crust may has been produced by direct melting of hydrated peridotite. However, the conditions, mechanisms and necessary ingredients of such production remain elusive. To fill this gap, we have conducted experiments of serpentinite melting in the presence of variable proportions of basaltic melt, at typical conditions of the shallow lithosphere and asthenosphere. These experiments revealed formation of silica-rich liquids, which are similar to tonalite-trondhjemite-granodiorite magmas (TTG) identified in modern terrestrial oceanic mantle settings. Our results suggest a new mechanism of aqueous fluid-assisted partial melting of peridotite that may have operated on the early Earth and Mars just after the solidification of an ultramafic-mafic magma ocean, leading to the formation of the first embryos of continental crust. The proposed mechanism of the continental crust formation may have been predominant before the onset of plate tectonics.
Keywords
Cite
@article{arxiv.2003.01508,
title = {Planetary Felsic Crust Formation at Shallow Depth},
author = {Anastassia Y. Borisova and Nail R. Zagrtdenov and Michael J. Toplis and Wendy A. Bohrson and Anne Nedelec and Oleg G. Safonov and Gleb S. Pokrovski and Georges Ceuleneer and Ilya N. Bindeman and Oleg E. Melnik and Klaus Peter Jochum and Brigitte Stoll and Ulrike Weis and Andrew Y. Bychkov and Andrey A. Gurenko and Svyatoslav Shcheka and Artem Terehin and Vladimir M. Polukeev and Dmitry A. Varlamov and Kouassi E. A. Chariteiro and Sophie Gouy and Philippe De Parseval},
journal= {arXiv preprint arXiv:2003.01508},
year = {2020}
}
Comments
62 pages, 9 figures, submitted to Frontiers in Earth Science