Chemical Weathering in Small Mountainous Rivers of Southern Italy and Northern Spain

Abstract

Since the seminal work of Milliman and Syvitski (J Geol 100:525–544, 1992), there has been interest in evaluating the significance of small mountainous river (SMRs) systems and their role in the transport of both solutes, and especially sediments, to the world ocean. Although some data exist from portions of the Earth’s mountainous regions, the majority of this work has been focused in the western Pacific Ocean and Caribbean regions. During those previous studies, workers have sought to evaluate the interconnection between physical erosion and chemical erosion rates. We report herein on the riverine geochemistry of five rivers draining northern Spain and six rivers draining southern Italy. The geochemistry of these rivers is dominated by calcium carbonate weathering and input from either evaporite dissolution or marine aerosols, or both. Silicate mineral weathering is also occurring but it is not the dominant process. Using previously tabulated annual total suspended load data, we have calculated both physical and chemical erosion yields from seven of the eleven rivers under investigation where complete data sets are available. The physical yields are much higher in the Italian rivers, while chemical yields of all rivers are in a similar range. Our work adds new information on SMRs from geographical regions that have not previously been evaluated within this global context.