Study of colors and degrees of weathering of granitic rocks by visible diffuse reflectance spectroscopy

Abstract

Diffuse reflectance spectroscopy and colorimetry have been applied to study the colors of powdered granitic rocks with different degrees of weathering. As a result, FeO(OH) was considered to be the source of the yellow-brownish color of the weathered rock powders. FeO(OH) contents were determined by diffuse reflectance spectroscopy based on the Kubelka-Munk function and found to increase during weathering. The FeO(OH) contents can be hence taken as a quantitative indicator of the degree of weathering. © 1989, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.