The complexity of mineral dissolution as viewed by high resolution scanning Auger microscopy: Labradorite under hydrothermal conditions

Amorphous Aluminum Hydroxide Formed at the Earliest Weathering Stages of K-Feldspar

“…Similarly, the present spherical material can simply be considered formed from a solution containing SO42-, which may be supplied from acid rain. The surface compositions of the feldspars that reacted experimentally with acid solutions tend to show a decrease in alkali cations and AI, and an increase in Si (Casey et al 1988(Casey et al , 1989Hochella et al 1988;Muir et al 1989Muir et al , 1990Petit et al 1989;Nesbitt et al 1991). On the contrary, Al-enriched layers at the surface of naturally weathered feldspars have been confirmed by EDX (Nixon 1979) and secondary ion mass spectroscopy (Nesbitt and Muir 1988).…”

Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona: Electron microscopic characterization

“…During the course of the last twenty years, there have been many arguments and counter-arguments advanced over whether such a layer exists, based on various analytical techniques, the details of which we shall omit here but readers are referred to Blum and Stillings (1995) and Brantley (2004). However, it has been generally agreed, until lately (see below), that this layer was confirmed by a variety of spectroscopic and ion beam techniques, mostly on laboratory leached feldspars in extremely acidic to acidic solutions (Schott and Petit, 1987;Casey et al, 1988;Hochella et al, 1988;Nesbitt and Muir, 1988;Casey et al, 1989a;Petit et al, 1989; Hellmann K-feldspar amorphous 6.00nm Fig. 9.…”

Porosity and surface area evolution during weathering of two igneous rocks

“…The initial growth of nanometer-scale porosity (here termed nanoporosity) is poorly understood (Montgomery and Brace, 1975;White et al, 1996;Putnis, 2002;Navarre-Sitchler et al, 2009). For example, although the health of terrestrial ecosystems relies on soil production, the rates of surface area change during water infiltration into rock cannot yet be predicted because our fundamental understanding of the water-rock interface inside rocks is limited (Hochella et al, 1988). This limitation is one of the reasons we cannot accurately extrapolate laboratory reaction rates to the field in predictive numerical models (NavarreSitchler and Brantley, 2007;Navarre-Sitchler et al, 2011).…”