干旱区生态环境知识资源中心

We studied a soil-geomorphic unit with a stonelayer at the Cape Peninsula, South Africa, for which there is no previous documented research, to characterize the soils and draw inferences regarding their pedogenesis and palaeoenvironment aspects. Mineralogy and element geochemistry were determined using XRD and XRF respectively; micromorphology by thin section description. Physicochemical properties were determined by routine procedures. The operational pedogenic process in the buried horizons include plinthization; and in the younger overlying soil, podzolization. Element abundance followed SiO2 > Al2O3> Fe2O3 > TiO2. Variations in climate and parent material are the principal causes of differences in the soil properties. The stonelayer appears to have been deposited as a lag by a palaeoriver as the energy decreased and the material was later mixed with the soil matrix by turbation. Two regional climate cycles are in evidence: a relatively warm and humid subtropical climate which gave rise to the formation of the buried palaeosol and a drier, more seasonal semi-arid Mediterranean climate under which the soils overlying the stone line are currently forming. Like many other places, the Cape Peninsula has also been subjected to global climate oscillations. Palaeosol-based proxies are capable of providing insights into palaeoenvironments. (C) 2014 Elsevier B.V. All rights reserved.