Dissolution-reprecipitation and self-assembly of serpentine nanoparticles preceding chrysotile formation: Insights into the structure of proto-serpentine

摘要: Any poorly crystalline serpentine-type mineral with a lack of recognizable textural or diffraction features for typical serpentine varieties (i.e., chryotile, lizardite, and antigorite) is usually referred to as proto-serpentine. The formation the so-called proto-serpentine seems ubiquitous in serpentinization reactions. It related dissolution-precipitation strongly reactive particles prior true (e.g., veins where both chrysotile are described). However, structural characteristics its relation remain unclear. In this study model describing transformation from presented based on experimental synthesis using thermogravimetric analyses, transmission electron microscopy, high-energy X-ray pair distribution function analyses. combination high-resolution TEM enables resolve local order neo-formed their structuration processes occurring during pure first three hours reaction). individual nanotubes preceded by small nanocrystals that already show short-range order, forming porous anastomosing hydrophilic crystallites mixed brucite. This followed hierarchical aggregation into fiber-like structure. These flake-like subsequently stack concentric layers Finally, individualization homogeneous diameter lengths (several hundreds nanometer length) observed. competitive precipitation brucite transient incipient reaction indicates serpentine-particle operate form chrysotile. sheds light mineralization sets milestone toward identification factors controlling polymorph selection mechanisms fascinating system.