Parent material properties of two Mediterranean badland sites: The impact on erosion dynamics

Badland landscapes are very widespread throughout a number of Italian regions. They consist of landforms carved into clayey deposits and are known as calanchi and biancane. Extensive literature on Mediterranean badlands areas has pointed out how, together with geological and climatic factors as well as human impact, more local conditions, such as parent material properties, play a relevant role in explaining the rapid erosion intensities, as well as the development of different slope landforms in these sites (BATTAGLIA et alii, 2002; FAULKNER et alii, 2000; GERITS et alii, 1997; TORRI et alii, 1994, PICCARRETA et alii, 2006; SUMMA et alii, 2007; PULICE et alii, 2012; VERGARI et alii, 2012). Mineralogical and physico-chemical composition of samples from badlands sites of Central and Southern Italy (Fig. 1) have been investigated in order to better understand the variability of mean erosion rates measured in different eroded landforms developed in the two study areas as well as to compare the results with respect to the triggering and development of different badlands forming processes in the two areas. Central Italy site is located in the Upper Orcia Valley (Tuscany), where Plio-Pleistocene marine deposits, filling NW– SE elongated sedimentary basins have been uplifted during the Quaternary, due to volcanic activity, up to several hundreds of meters above present sea level (Fig.1). Southern Italy site is situated in the Crotone area, (Calabria), at the Plio-Pleistocene clays of the Crotone Basin. (Fig.1) Tab.1 summarizes the mean climatic features of the study areas. Results of grain size analyses, pore water soluble ions concentration on a saturation extract and the mineralogical composition, performed using an Rigaku X-ray diffractometer, are discussed, in order to unravel the role of main topographic and geological erosion factors.