The durability of rocks - Developing a test of rock resistance to chemical weathering

Abstract

Dissolution rates of 39 rock-forming minerals were determined at 20 °C and 100 °C and different pH values, using experimental set-ups which achieve near-zero cation concentrations. Weathering rates in nature for rock above surface were estimated from data in this study and data in the literature. Extraction in a Soxhlet extractor with boiling 2.5 m acetic acid causes an acceleration of such estimated natural weathering rates by a factor of 0.25 X 103 to 7 X 104 for nearly all important rock-forming minerals, including the carbonates. The applicability of such a comparative test for rock resistance to chemical weathering was corroborated by testing 32 different rocks and building stones. Run times of only one to four days were needed for a reliable result.