Late Quaternary geomorphological processes and landscape evolution in the Khur Basin, central Iran

Abstract. The interior of the Central Iranian Plateau is an important area for the study of the palaeoenvironmental controls of early human dispersal in arid regions. In the now hyper-arid region, human migrations may have been affected by the major Quaternary climatic changes. However, due to the difficult access and harsh climate in the central desert, there are scarce palaeoenvironmental data available to reconstruct the interplay between migration of past cultures and environmental change. In the Khur Basin, located in the central part of the Iranian Plateau and on the eastern edge of the central Great Kavir, geomorphological landscape archives have been preserved that provide valuable information about the landscape evolution and climate dynamics of this characteristic desert region. As the spatiotemporal relationships between the dominant geomorphological forms and processes in this area have mostly been studied in isolation, this study adopted an integrative approach to better assess the diverse interactions. This involved geomorphological mapping and detailed field-based geomorphological and stratigraphical analyses of 12 sedimentary sequences distributed over eight geomorphic units of the Khur Basin. The resulting relative chronological classification of the morphostratigraphy suggests a logical sequence of six main phases of landscape evolution. By combining our mapping results with dated geoarchives of the region, a tentative chronology was developed. The early stages as observed in the stratigraphically oldest preserved landforms were characterised by a sequence of different processes, including pediment erosion, alluvial fan and dune formation, and soil development, and probably date to the phase before and during Marine Isotope Stage (MIS) 3. The subsequent landforms and deposits are to be interpreted as a result of alluvial fan progradation into the basin interior as well as dune development, which are probably attributable to the cold and arid conditions during the Last Glacial Maximum (LGM). The most recent morphostratigraphic findings correlate with the combined effects of pedological and geomorphological processes, including the formation of gypsum-rich soils, sand dune reactivation, and the deflation of playa surfaces. These findings indicate an increasing aridity in the area, which is often associated with the climatic development of the Holocene. Through the systematic integration of stratigraphical and geomorphological evidence, this study provides a first comprehensive historical–genetic model of landscape evolution in the Khur Basin.