Measurement of Cl⁻ : Br⁻ Ratios in the Porewater of Clay-Rich Rocks—A Comparison of the Crush-and-Leach and the Paper-Absorption Methods

Figure 1

Pore-scale conceptual model for clay-rich sedimentary rock. A variety of clay minerals are depicted, including 1 : 1 clay minerals, such as kaolinite, 2 : 1 nonswelling clay minerals, such as illite, and 2 : 1 swelling clay minerals such as smectite. The negatively charged surfaces of these minerals are balanced with cation-rich water in the DDL and in the interlayer positions of the swelling clay minerals. Mobile water is found in the larger pore spaces.