Saleh Sanjari

Topography, parent material, and climate are critical factors influencing pedogenesis and clay mineralogy of soils. There is a paucity of data regarding the soils and sediments of the Jazmurian Watershed in south-central Iran. This study selected various landforms, including rock and mantled pediments, alluvial fans, piedmont plains, lowlands, and playa characterized by igneous and sedimentary parent materials and situated within aquic, xeric, and aridic soil moisture regimes, to investigate soil genesis and clay mineralogy in the region. The findings indicated that the most significant soil development occurred on rock and mantled pediments, as well as on older alluvial fan sediments, in contrast to the less developed soils found on younger alluvial fan deposits. The clay minerals included smectite, illite, chlorite, palygorskite, and kaolinite. The presence of palygorskite in the sedimentary soils was attributed to inheritance from the parent material, while in soils derived from igneous parent material, it was formed through pedogenic processes. Pedogenic features associated with calcium carbonate were observed in both aridic and xeric soil moisture regimes. The occurrence of clay pedogenic features in the arid regions of the watershed may suggest a historical paleoclimate with greater moisture availability. Conversely, lenticular shapes, interlocked plates, and gypsum infillings were exclusively noted in the arid regions and lower elevations of the watershed, reflecting the current arid climate.