『Abstract
Reactions involving feldspars are of great importance in the
environment, influencing geochemical cycles in many ways. Dissolution
of feldspars has been widely studied in the laboratory, with attempts
being made to reproduce and understand the processes of “weathering”
as seen in the environment. It has long been recognised that weathering
of feldspars involves the attachment and detachment of atoms at
the surface of the mineral. A wide range of factors influences
the reactions involved, from the composition of the feldspar to
the nature of the solution, but it is generally accepted that
weathering leads to the presence of a leached layer, with a composition
different from both the bulk mineral and the fluid. The aim of
this paper is to review recent work carried out on feldspars,
focusing particularly on developing an under standing of the leached
layer using both spectroscopic methods (including Secondary Ion
Mass Spectroscopy and X-ray Photoelectron Spectroscopy), and microscopic
imaging techniques (including Atomic Force Microscopy and Scanning
Electron Microscopy) to follow changes at the mineral/solution
interface. Contrasting models of surface evolution are discussed.
Keywords: feldspar; weathering; leached layer; stoichiometry;
dissolution-reprecipitation』
1. Introduction
2. Determination of surface chemical composition, structure and
morphology of feldspars after dissolution
2.1. Secondary ion mass spectroscopy (SIMS)
2.2. Ion beam techniques
2.3. X-ray photoelectron spectroscopy (XPS)
3. Study of the surface microtopography
4. Comparisons between laboratory experiments and naturally weathered
feldspars
5. Summary and overall conclusions
References