Origin of biancane and calanchi in East Aliano, southern Italy

Areas underlain by Plio-Pleistocene marine mudstone in south Italy are severely affected by denudation processes and have been transformed into badlands with two well defined types of landform: biancane and calanchi. In this paper, factors that contributed to the development of the Aliano badlands and particularly to the geneses of biancane and calanchi have been studied, based on aerospace data; field observations on geomorphic processes and geological structure; laboratory measurements of soil and bedrock samples; and morphometric analysis. Several maps and spatial data were prepared to describe factors which are thought to be related with landform formations, such as lineament distribution, elevation, slope, and pipe distribution. Morphometric characteristics of biancane and calanchi (steepness and slope length), dominant active processes, and the dip/orientation of beddings, joints, and fault planes were investigated, and 71 samples of soils and bedrock were taken to characterise their properties. The results of the analyses of the soil/bedrock samples show no significant differences in their properties between biancane and calanchi. Field observations do not support the idea that biancane are the final product of calanchi development, but support the hypothesis that biancane and calanchi are formed under different terrain conditions related to structural patterns and denudation processes of highly erodible materials. The origin of biancane is associated with highly dissected surfaces along a reticular system of small joints. In contrast, calanchi are formed on steep wall-like slopes along larger lineaments where the rate of incision into the slopes surpasses the denudation of the densely vegetated back-slope. (c) 2006 Elsevier B.V. All rights reserved.