Mineral dissolution and reprecipitation mediated by an amorphous phase.

Nat Commun 2018 04 24;9(1):1637. Epub 2018 Apr 24.

GeoForschungsZentrum Potsdam (GFZ), Telegrafenberg, Potsdam, 14473, Germany.

Fluid-mediated mineral dissolution and reprecipitation processes are the most common mineral reaction mechanism in the solid Earth and are fundamental for the Earth's internal dynamics. Element exchange during such mineral reactions is commonly thought to occur via aqueous solutions with the mineral solubility in the coexisting fluid being a rate limiting factor. Here we show in high-pressure/low temperature rocks that element transfer during mineral dissolution and reprecipitation can occur in an alkali-Al-Si-rich amorphous material that forms directly by depolymerization of the crystal lattice and is thermodynamically decoupled from aqueous solutions. Depolymerization starts along grain boundaries and crystal lattice defects that serve as element exchange pathways and are sites of porosity formation. The resulting amorphous material occupies large volumes in an interconnected porosity network. Precipitation of product minerals occurs directly by repolymerization of the amorphous material at the product surface. This mechanism allows for significantly higher element transport and mineral reaction rates than aqueous solutions with major implications for the role of mineral reactions in the dynamic Earth.

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http://dx.doi.org/10.1038/s41467-018-03944-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5915427PMC
April 2018
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References

(Supplied by CrossRef)

A Putnis et al.
Rev. Mineral. Geochem. 2009

A Putnis et al.
Science 2014

E Ruiz-Agudo et al.
Chem. Geol. 2014

L Spruzeniece et al.
Nat. Commun. 2017

D Forsyth et al.
Geophys. J. Int. 1975

J Hunen Van et al.
Annu. Rev. Earth Planet. Sci. 2012

JJ Ague et al.
Nat. Geosci. 2014

SF Cox et al.
Ore Geol. Rev. 1987

PT Cardew et al.
Proc. R. Soc. Lond. A: Math., Phys. Eng. Sci. 1985

EH Oelkers et al.
Geochim. Cosmochim. Acta 2009

CV Putnis et al.
Elements 2013

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