Physical-chemical and mineralogical properties of parent materials and their relationship with the morphology of badlands

Badlands are present throughout the world, but not everywhere do they have the same morphology. The main objective of this study is to try to understand why these different morphologies occur by analysing the physical-chemical and mineralogical characteristics of the parental material in which badlands have developed. The study was carried out in three areas of the Region of Murcia (south-east Spain): Abanilla, Mula and Gebas. Several analyses were carried out: (i) field analysis (orientation, slope, length and shape of the slope, presence and characteristics of the rills, vegetation, vegetation pedestals, exposed roots, stoniness, physical and biological crusts, saline efflorescence, cracks, popcorn, piping processes, sedimentation areas and mass movements); (ii) physical-chemical analysis of the soils (colour, texture, aggregate stability, bulk density, organic matter, pH, electrical conductivity, cations and cation exchange capacity, total or equivalent calcium carbonate, sodium absorption ratio and exchangeable sodium percentage); and (iii) mineralogical analysis. The results of the analyses reveal how the rounded shapes in the badlands that appear in Abanilla have significant differences with respect to the angled shapes of Mula and Gebas, which could explain the different morphologies. In general, Abanilla has very small amount of sand, higher bulk density, small amount of organic matter, lower cation exchange capacity, and very high salinity, as shown in the values of electrical conductivity, sodio, SAR and ESP. On the other hand, similarities were found between the badlands of the Region of Murcia with the calanchi (angled shapes) and biancane (rounded shapes) of Italy. (C) 2020 Elsevier B.V. All rights reserved.