Pedosphere 23(3): 359--371, 2013
ISSN 1002-0160/CN 32-1315/P
©2013 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Factors affecting the occurrence of palygorskite in central Iranian soils developed on Tertiary sediments |
S. HOJATI1, H. KHADEMI1 , A. FAZ CANO2, S. AYOUBI1 and A. LANDI3 |
1 Department of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111 (Iran)
2Agrarian Science and Technology Department, Technical University of Cartagena, Paseo Alfonso XIII, 52.30203, Cartagena, Murcia (Spain)
3Department of Soil Science, College of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz (Iran) |
| ABSTRACT |
| Limited information is available on the distribution and origin of palygorskite in soils developed on Tertiary sediments as the major soil parent materials in central Iran and other Middle Eastern countries. The objectives of this study were to determine the distribution and origin of palygorskite in soils developed on Tertiary sediments, and to identify the major soil properties that influence palygorskite distribution in the soils studied. Sixteen soil profiles developed on Paleocene, Eocene, Oligocene, Oligocene-Miocene, Miocene and Pliocene sediments were studied by X-ray diffraction analysis, transmission electron microscope, and scanning electron microscopy. Physicochemical characteristics of the soils and sediments including particle size distribution, pH, electrical conductivity, organic carbon, gypsum, carbonates, and soluble Si, Ca and Mg were determined. The principal component analysis was used to establish the relationships between palygorskite and the physicochemical characteristics of the soils studied. Results showed that clay fraction of all the soils in the study area was dominated by palygorskite. The highest amount of palygorskite was found in horizons where simultaneous accumulation of both carbonates and gypsum occurred. Limited amount of palygorskite was found in salic and calcic horizons. Palygorskite seemed to be of eolian origin in the surface horizon of all the soils. Using principal component analysis, the soluble Mg/Ca ratio, pH, soluble Si and gypsum contents were identified as the most important factors affecting the distribution and genesis of palygorskite in the soils studied. Results might suggest the neoformation of palygorskite by precipitation from solutions in which evaporation fluxes were very high. However, palygorskite in soils developed on Tertiary sediments in central Iran seems to be of both inherited and pedogenic origins. |
| Key Words: clay minerals, discriminant analysis, gypsum, parent materials, principal component analysis |
| Citation: Hojati, S., Khademi, H., Faz, C., Ayoubi, S. and Landi, A. 2013. Factors affecting the occurrence of palygorskite in central Iranian soils developed on Tertiary sediments. Pedosphere. 23(3): 359-371. |
|
View Full Text
|
|
|
|
