Feldspar weathering laboratory studies

Rates estimated in the above studies are shown in Table I. Watershed-scale geochemical mass balance studies yield calculated feldspar weathering rates one to three orders of magnitude slower than rates determined in laboratory experiments. 

Several simple experimental systems that simulate some aspect of the groundwater environment have been used to study the breakdown of individual minerals. These kinetics studies have encompassed quartz (Brantley et al., 1986), feldspars (Holdren and Berner, 1979 Holdren and Speyer, 1985), pyroxenes and amphiboles (Berner and Schott, 1982 Schott and Berner, 1985), carbonates (Berner, 1978), and glasses (White, 1983). The relative stability observed in laboratory weathering is consistent with field-based observations however, experimental rates appear to be faster than those in natural systems. 

All feldspars are very apt to undergo alteration, both from hydrothermal solutions in rock systems and from the normal processes of weathering that result in primary rocks being converted to soils. There have been many field studies of rock alteration by geologists, and in parallel with this, a number of studies in the laboratory of the alteration of feldspars under hydrothermal conditions. For example, Morey and Chen [1955] studied the action of hot water under pressure on feldspars Tchoubar and Oberlin [1963] experimentally weathered albite by water containing CO2 in solution and observed oriented overgrowth of boehmite using electron optical techniques and Brindley and Radoslovich [1956] also observed the formation of boehmite on albite under mildly acidic hydrothermal conditions. ... 

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