Evidence of paleoprocesses in some poorly developed soils on consolidated material in the Sierra de Carrascoy (SE Spain)

Four representative profiles of poorly developed soils on consolidated material were studied in the Sierra de Carrascoy (SE Spain). The soils, with A-A/R or A-C/R type profiles, have medium–low contents of organic carbon and nitrogen, and calcium carbonate occurs in only one of the profiles. The pH in aqueous suspension is slightly alkaline. The cation exchange capacity is medium–low, but varies slightly between profiles, and the electrical conductivity of the saturation extract is low. There are wide textural differences. The clay fractions contain illite, kaolinite, vermiculite, smectites, chlorite, quartz and feldspars. The heavy fraction of the fine sand contains mainly opaque minerals and alterites, with some resistant minerals of metamorphic origin. The profiles are classified by F.A.O-I.S.R.I.C.-I.S.S.S. [World Reference Base for Soil Resources. World Soil Resources Reports 84. F.A.O., Rome, 1998] as Calcaric, Eutric and Hyperskeletic Leptosols. According to Soil Survey Staff [Soil Taxonomy. A basic system of soil classification for making and interpreting soil surveys, 2nd edn., United States Department of Agriculture. Natural Resources Conservation Service. US Government Printing Office, Washington, DC, 1999], they are all Lithic and Typic Xerorthents and Lithic Xeric and Xeric Torriorthents. The principal present-day pedogenetic processes in these soils are humification and clay formation. However, profile 1 has evolved from a fersiallitic soil with clay accumulation, although these features have almost disappeared because of erosion and modern humification, pedoturbation and recalcification. Its relict features consist of the remains of a paleoargic horizon inherited from earlier climatic conditions, which was later truncated and is now preserved only in more stable physiographic positions.