Mineral dissolution and reprecipitation mediated by an amorphous phase
Artikel i vetenskaplig tidskrift, 2018

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.

Författare

Matthias Konrad-Schmolke

Göteborgs universitet

Ralf Halama

Keele University

Richard Wirth

Deutsches GeoForschungsZentrum (GFZ)

Aurélien Thomen

Chalmers, Kemi och kemiteknik

Nico Klitscher

Deutsches GeoForschungsZentrum (GFZ)

Luiz Morales

Eidgenössische Technische Hochschule Zürich (ETH)

Anja Schreiber

Deutsches GeoForschungsZentrum (GFZ)

Franziska D.H. Wilke

Deutsches GeoForschungsZentrum (GFZ)

Nature Communications

2041-1723 (ISSN)

Vol. 9 1 1637

Ämneskategorier

Mineral- och gruvteknik

Oorganisk kemi

Geokemi

DOI

10.1038/s41467-018-03944-z

Mer information

Senast uppdaterat

2019-01-16