Abrasion pH, an Index of Chemical Weathering

Willard H. Grant
Department of Geology, Emory University, Atlanta, Georgia 30322

Abstract: If a series of rock samples with granitic composition in various stages of chemical weathering is ground in a mortar with distilled water and the pH of the slurry produced is determined, it will be evident that the pH declines as the weathering increases. This relationship can be made useful by plotting abrasion pH against some other index of weathering such as the percentage of clay mineral or the bulk density of the weathered rock. Factors controlling abrasion pH are the cations such as K, Na, Ca, and Mg and the amount of clay mineral present.

Clays and Clay Minerals; August 1969 v. 17; no. 3; p. 151-155; DOI: 10.1346/CCMN.1969.0170303
© 1969, The Clay Minerals Society
Clay Minerals Society (www.clays.org)