The assessment of weathering stages in granites using an EC/pH meter

The weathering of granite encompasses a wide range extending from slightly weathered rock to saprolite to soil. Although many different methods are available for quantifying the amount of chemical or physical weathering in granites, dissolution rate as a method for estimating the degree of chemical weathering in these rocks was not thoroughly investigated. This study sought to identify a method for quantifying weathering stages in granite, based on both the chemical and physical properties of the rock. Using the weathering profile of granites from two quarries in the Chugoku region of western Japan, a simple dissolution experiment (measured with an electrical conductivity meter for 10 min) recorded the differences in dissolution rates, which reflects the chemical weathering stages in granites. The combination of the dissolution rate and the p-wave velocity produces a diagram that gives the chemical and physical properties of the weathered rock body in a single chart.