Clay fabric as an indicator of cyclic changes in an estuarine palaeo-environment: Lower Pleistocene, northern Campine Area, Belgium

SEM photographs of the Turnhout Member (Lower Pleistocene), reveal a vertical cyclicity of 2 main clay-fabric types: (a) face-to-face domains and (b) edge-to-face domains, each of them indicating the existence of respectively dispersed particles deposited in a salt-water environment, the transition being marked by intermediate clay-fabric types. It is suggested that the sequence corresponds to fluctuations in the position of the fluvial-marine equilibrium, related to important changes in river runoff of tidal amplitude. These observations indicate the utility of applying clay-fabric analyses to achieve a higher resolution in palaeo-environmental interpretations