Soils of semiarid regions of Dehdasht and Choram in
Southwestern Iran have formed on alluvium derived from mixed
calcareous-gypsiferous materials from Lower Miocene to Upper Pliocene. In order
to characterize and classify the soils and to determine the soil-landscape
relationship in the area, nine pedons located on different physiographic
positions including plateau, river alluvial plain, piedmont
plain, alluvial plain and alluvial fan have been described, sampled and
analyzed. Physicochemical analyses, clay mineralogy and micromorphological
studies were performed. The
results showed that topography and parent material were two important soil
forming factors affecting soil formation in the area. The soils were dominated
by carbonate, gypsum, and clay illuviation and accumulation. More developed
soils were found on the stable plateau and piedmont plain. Clay illuviation and
argillic horizon development in soils of the more stable alluvial plain were
assumed to be relict features from presumably more humid climates.
Palygorskite, illite, chlorite, smectite, kaolinite, and quartz clay minerals
were identified in almost all physiographic surfaces, but more palygorskite and less
smectite were found in the soils with gypsiferous parent materials. Observations by SEM revealed the occurrence of
neoformed palygorskite as thread-like faces and coating of gypsum crystals and marly matrix. Coating and infilling of gypsum and calcite
crystals in voids and channels were common pedofeatures observed in the soils
studied. Two different distribution patterns of Fe-Mn oxides
were identified in aquic and non-aquic soils.
Journal Section | Articles |
---|---|
Authors | |
Publication Date | April 1, 2018 |
Published in Issue | Year 2018 Volume: 7 Issue: 2 |