TY - JOUR
T1 - The fate of waterwithin Earth and super-earths and implications for plate tectonics
AU - Tikoo, Sonia M.
AU - Elkins-Tanton, Linda
N1 - Funding Information:
S.M.T. was supported by the Rutgers University School of Arts and Sciences. L.T.E.-T. was supported by Arizona State University.
Publisher Copyright:
© 2017 The Author(s) Published by the Royal Society. All rights reserved.
PY - 2017/5/28
Y1 - 2017/5/28
N2 - The Earth is likely to have acquired most of its water during accretion. Internal heat of planetesimals by short-lived radioisotopes would have caused some water loss, but impacts into planetesimals were insufficiently energetic to produce further drying. Water is thought to be critical for the development of plate tectonics, because it lowers viscosities in the asthenosphere, enabling subduction. The following issue persists: if water is necessary for plate tectonics, but subduction itself hydrates the upper mantle, how is the upper mantle initially hydrated? The giant impacts of late accretion created magma lakes and oceans, which degassed during solidification to produce a heavy atmosphere. However, some water would have remained in the mantle, trapped within crystallographic defects in nominally anhydrous minerals. In this paper, we present models demonstrating that processes associated with magma ocean solidification and overturn may segregate sufficient quantities of water within the upper mantle to induce partial melting and produce a damp asthenosphere, thereby facilitating plate tectonics and, in turn, the habitability of Earthlike extrasolar planets. This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'.
AB - The Earth is likely to have acquired most of its water during accretion. Internal heat of planetesimals by short-lived radioisotopes would have caused some water loss, but impacts into planetesimals were insufficiently energetic to produce further drying. Water is thought to be critical for the development of plate tectonics, because it lowers viscosities in the asthenosphere, enabling subduction. The following issue persists: if water is necessary for plate tectonics, but subduction itself hydrates the upper mantle, how is the upper mantle initially hydrated? The giant impacts of late accretion created magma lakes and oceans, which degassed during solidification to produce a heavy atmosphere. However, some water would have remained in the mantle, trapped within crystallographic defects in nominally anhydrous minerals. In this paper, we present models demonstrating that processes associated with magma ocean solidification and overturn may segregate sufficient quantities of water within the upper mantle to induce partial melting and produce a damp asthenosphere, thereby facilitating plate tectonics and, in turn, the habitability of Earthlike extrasolar planets. This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'.
KW - Extrasolar planets
KW - Magma ocean
KW - Planet formation
KW - Plate tectonics
KW - Super-earths
KW - Water
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U2 - 10.1098/rsta.2015.0394
DO - 10.1098/rsta.2015.0394
M3 - Article
C2 - 28416729
AN - SCOPUS:85017632240
VL - 375
JO - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
JF - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
SN - 0962-8428
IS - 2094
M1 - 20150394
ER -