Processes that control the deposition and transformation of clay minerals in the sedimentary and diagenetic environment will be reviewed. The origins of clay minerals in sediments by inheritance, transformation and neoformation will be covered and the relationships of sediments to soils. The transition from mud to slate in the Earth's crust is accompanied by a number of interesting clay mineral transformations which will be addressed in the second part. We shall take a look at the characteristics of these transformations and discuss the mechanisms involved. The kinetics of clay mineral crystal growth will be addressed in relation to some recent advances in X-ray diffraction.

In a practical part different standard procedures for the fractionation, separation and XRD-preparation (for preferred orientation) of clays are also presented. Advantages and disadvantages of these procedures will be evaluated.

Fig. 1: Chlorite (SEM-photograph) and structural model