Patterns in river channel sinuosity of the Meuse, Roer and Rhine rivers in the Lower Rhine Embayment rift-system, are they tectonically forced?

Abstract

The tectonic and fluvial setting of the Rhine-Meuse river system in the Lower Rhine Embayment rift system is exceptionally well known. The 19th century, pre-regulation river courses of three rivers are used to study a postulated sinuosity response to faulting. The fault-perpendicular Meuse River shows patterns of sinuosity changes at different spatial scales. The large-scale (>5 km) sinuosity changes are related mainly to the faulting-induced changes of the subsurface lithology, determining the bed and bank characteristics. However, at a smaller scale, some fault-related channel sinuosity anomalies are observed. The fault-parallel Roer River shows sinuosity changes related to a normal, non-tectonic longitudinal gradient change. Sinuosity patterns of the Rhine River are predominantly related to lithological differences and reduced incision rates. Sinuosity can thus be an indicator of tectonic motions, but gradient, subsurface lithology and river bank composition determine sinuosity as well. Therefore, a sinuosity change is no proof for fault activity. On the other hand, the absence of a sinuosity change does not imply inactivity of a fault at geological time-scales.