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Application of Auger Electron Spectroscopy to studies of chemical weathering
Author(s) -
Mogk David W.
Publication year - 1990
Publication title -
reviews of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.087
H-Index - 156
eISSN - 1944-9208
pISSN - 8755-1209
DOI - 10.1029/rg028i004p00337
Subject(s) - auger electron spectroscopy , chemical composition , dissolution , weathering , silicate minerals , materials science , analytical chemistry (journal) , mineralogy , electron spectroscopy , electron , spectroscopy , auger , energy dispersive x ray spectroscopy , silicate , x ray photoelectron spectroscopy , chemistry , atomic physics , geology , scanning electron microscope , chemical engineering , physics , organic chemistry , chromatography , quantum mechanics , geomorphology , nuclear physics , engineering , composite material
Auger electron spectroscopy (AES) is a surface‐sensitive analytical technique that derives from the interaction of an electron beam and atoms in residence at the surface of a sample; inner shell ionizations produce Auger electrons, which have an escape depth of only a few tens of angstroms. This technique has numerous applications to chemical weathering and other geochemical processes that operate on mineral surfaces. The analytical capabilities of AES include chemical analyses of the near surfaces of minerals for all elements except H and He, semiquantitative analysis of the relative atomic concentration of surface components, high lateral spatial resolution (>0.1 µm) of the analyzed area to determine the composition of discrete domains on mineral surfaces and to identify unknown minerals on a submicrometer scale, and elemental depth profiling using an ion sputter gun. These capabilities can be used to address the nature of mineral dissolution processes, providing discrimination among mechanisms such as congruent versus incongruent dissolution, surface‐controlled reactions versus diffusion through a leached or armored layer, uniform versus heterogeneous distribution of reacted layers, and identification of alteration phases. The effectiveness of AES analysis is limited by charging of nonconducting samples (e.g., silicate minerals) and sample degradation under the electron beam; these problems may be mitigated by careful sample preparation and instrument operation procedures. AES can be used in concert with numerous other microbeam techniques to fully characterize the surface composition and structure of reacting minerals.