XRD patterns of whole rock material were recorded using a PANalytical X'Pert PRO MPD θ - θ diffractometer (Co-Kα radiation generated at 40 kV and 40 mA). The samples were investigated from 3° to 80° 2 θ with a step size of 0.03° 2 θ and a measuring time of 3 sec per step. Quantitative Rietveld refinements of the experimental XRD data were conducted using the software Profex/BGMN (Döbelin & Kleeberg, 2015; Bergmann et al., 1998). Determination of cation exchange capacity (CEC) was carried out using always two different samples masses (typically 400 and 600 mg) according to the method of Meier and Kahr (1999), based on a Cu(II)triethylentetramine complex ("Cu-trien method") and measurement using VIS spectroscopy. According to Dohrmann et al. (2012), the analytical error as determined for high-CEC bentonites is generally smaller than ±3.9 cmol(+)kg⁻¹.

An empty field in the whole rock mineralogy tables indicates that the mineral was not detected.