The divergent fates of primitive hydrospheric water on Earth and Mars

Despite active transport into Earth’s mantle, water has been present on our planet’s surface for most of geological time1,2. Yet water disappeared from the Martian surface soon after its formation. Although some of the water on Mars was lost to space via photolysis following the collapse of the plan...

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Main Authors: Wade, Jon, Dyck, Brendan, Palin, Richard M., Moore, James Daniel Paul, Smye, Andrew J.
Other Authors: Earth Observatory of Singapore
Format: Article
Language:English
Published: 2017
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Online Access:https://hdl.handle.net/10356/86885
http://hdl.handle.net/10220/44211
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-868852020-09-26T21:38:11Z The divergent fates of primitive hydrospheric water on Earth and Mars Wade, Jon Dyck, Brendan Palin, Richard M. Moore, James Daniel Paul Smye, Andrew J. Earth Observatory of Singapore Geochemistry Inner planets Despite active transport into Earth’s mantle, water has been present on our planet’s surface for most of geological time1,2. Yet water disappeared from the Martian surface soon after its formation. Although some of the water on Mars was lost to space via photolysis following the collapse of the planet’s magnetic field3,4,5, the widespread serpentinization of Martian crust6,7 suggests that metamorphic hydration reactions played a critical part in the sequestration of the crust. Here we quantify the relative volumes of water that could be removed from each planet’s surface via the burial and metamorphism of hydrated mafic crusts, and calculate mineral transition-induced bulk-density changes at conditions of elevated pressure and temperature for each. The metamorphic mineral assemblages in relatively FeO-rich Martian lavas can hold about 25 per cent more structurally bound water than those in metamorphosed terrestrial basalts, and can retain it at greater depths within Mars. Our calculations suggest that in excess of 9 per cent by volume of the Martian mantle may contain hydrous mineral species as a consequence of surface reactions, compared to about 4 per cent by volume of Earth’s mantle. Furthermore, neither primitive nor evolved hydrated Martian crust show noticeably different bulk densities compared to their anhydrous equivalents, in contrast to hydrous mafic terrestrial crust, which transforms to denser eclogite upon dehydration. This would have allowed efficient overplating and burial of early Martian crust in a stagnant-lid tectonic regime, in which the lithosphere comprised a single tectonic plate, with only the warmer, lower crust involved in mantle convection. This provided an important sink for hydrospheric water and a mechanism for oxidizing the Martian mantle. Conversely, relatively buoyant mafic crust and hotter geothermal gradients on Earth reduced the potential for upper-mantle hydration early in its geological history, leading to water being retained close to its surface, and thus creating conditions conducive for the evolution of complex multicellular life. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Accepted version 2017-12-28T04:59:22Z 2019-12-06T16:30:55Z 2017-12-28T04:59:22Z 2019-12-06T16:30:55Z 2017 Journal Article Wade, J., Dyck, B., Palin, R. M., Moore, J. D. P., & Smye, A. J. (2017). The divergent fates of primitive hydrospheric water on Earth and Mars. Nature, 552, 391-394. 0028-0836 https://hdl.handle.net/10356/86885 http://hdl.handle.net/10220/44211 10.1038/nature25031 en Nature © 2017 Macmillan Publishers Limited, part of Springer Nature. This is the author created version of a work that has been peer reviewed and accepted for publication by Nature, Macmillan Publishers Limited, part of Springer Nature. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1038/nature25031]. 22 p. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Geochemistry
Inner planets
spellingShingle Geochemistry
Inner planets
Wade, Jon
Dyck, Brendan
Palin, Richard M.
Moore, James Daniel Paul
Smye, Andrew J.
The divergent fates of primitive hydrospheric water on Earth and Mars
description Despite active transport into Earth’s mantle, water has been present on our planet’s surface for most of geological time1,2. Yet water disappeared from the Martian surface soon after its formation. Although some of the water on Mars was lost to space via photolysis following the collapse of the planet’s magnetic field3,4,5, the widespread serpentinization of Martian crust6,7 suggests that metamorphic hydration reactions played a critical part in the sequestration of the crust. Here we quantify the relative volumes of water that could be removed from each planet’s surface via the burial and metamorphism of hydrated mafic crusts, and calculate mineral transition-induced bulk-density changes at conditions of elevated pressure and temperature for each. The metamorphic mineral assemblages in relatively FeO-rich Martian lavas can hold about 25 per cent more structurally bound water than those in metamorphosed terrestrial basalts, and can retain it at greater depths within Mars. Our calculations suggest that in excess of 9 per cent by volume of the Martian mantle may contain hydrous mineral species as a consequence of surface reactions, compared to about 4 per cent by volume of Earth’s mantle. Furthermore, neither primitive nor evolved hydrated Martian crust show noticeably different bulk densities compared to their anhydrous equivalents, in contrast to hydrous mafic terrestrial crust, which transforms to denser eclogite upon dehydration. This would have allowed efficient overplating and burial of early Martian crust in a stagnant-lid tectonic regime, in which the lithosphere comprised a single tectonic plate, with only the warmer, lower crust involved in mantle convection. This provided an important sink for hydrospheric water and a mechanism for oxidizing the Martian mantle. Conversely, relatively buoyant mafic crust and hotter geothermal gradients on Earth reduced the potential for upper-mantle hydration early in its geological history, leading to water being retained close to its surface, and thus creating conditions conducive for the evolution of complex multicellular life.
author2 Earth Observatory of Singapore
author_facet Earth Observatory of Singapore
Wade, Jon
Dyck, Brendan
Palin, Richard M.
Moore, James Daniel Paul
Smye, Andrew J.
format Article
author Wade, Jon
Dyck, Brendan
Palin, Richard M.
Moore, James Daniel Paul
Smye, Andrew J.
author_sort Wade, Jon
title The divergent fates of primitive hydrospheric water on Earth and Mars
title_short The divergent fates of primitive hydrospheric water on Earth and Mars
title_full The divergent fates of primitive hydrospheric water on Earth and Mars
title_fullStr The divergent fates of primitive hydrospheric water on Earth and Mars
title_full_unstemmed The divergent fates of primitive hydrospheric water on Earth and Mars
title_sort divergent fates of primitive hydrospheric water on earth and mars
publishDate 2017
url https://hdl.handle.net/10356/86885
http://hdl.handle.net/10220/44211
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