Use of rock tablet method to measure rock weathering and landscape denudation

Abstract

[EN]Rock weathering is a key component of the rock cycle that transforms rocks in sediments, soils and/or dissolves minerals to ions, and plays an important role in landforms development and landscape evolution. The quantification of weathering is often challenging due to the impact of measuring techniques on the rock itself and/or the assumptions required to perform the calculations. Among different methods used to quantify rock weathering, rock tablet method is one of the most widely used. The rock tablet method consists of cutting rock samples in a shape that allows precise calculation of their volume and surface. These rock pieces, often named tablets when they are flat, are dried, precisely weighed and exposed to the natural environment for certain amount of time. After retrieval, the same laboratory procedure is repeated, and from the weight loss, the weathering rate is calculated. When the density of the rock is known and it is reasonable to assume that the lost material is removed from the ground surface, the weight loss can be used to calculate denudation rates. This is the case in karst regions, where rock tablets are one of the most commonly used methods to calculate denudation. This simple and versatile method requires only a limited amount of laboratory equipment to be implemented which makes it very popular. However, experimental design, preparation of samples and calculations are not homogeneous among researchers, sometimes making the results of this method challenging to be evaluated and compared. In this paper we describe the rock tablet method, include its historical overview, review the most significant studies that have used this technique, highlight its limitations, introduce correction factors to minimize some of those limitations, and provide good practice recommendations to help other researchers to obtain comparable results around the world.