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Soil Genesis as Affected by Topography and Time in Highly Calcareous Parent Materials Under Semiarid Conditions in Iran
Author(s) -
Abtahi Ali
Publication year - 1980
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1980.03615995004400020025x
Subject(s) - calcareous , geology , chronosequence , soil water , carbonate , alluvium , geochemistry , inceptisol , soil salinity , salinity , clay minerals , entisol , soil science , geomorphology , chemistry , oceanography , paleontology , organic chemistry
Abstract Soil formation as affected by topography and time was studied in highly calcareous parent materials under the semiarid conditions of southern Iran. Soils of the 95,000‐ha Sarvestan basin were considered for this purpose. Topographic features of the Sarvestan basin were related to variations in soil texture and salinity. Slightly saline, coarse‐textured soils occurred at high elevations, whereas fine‐textured soils of higher salinity occurred at low elevations. Based on salinity status, these two general soil types were classified as Inceptisols and Aridisols, respectively. Soils comprising a chronosequence differed mainly in the redistribution and accumulation of carbonates. They ranged from those developed in Holocene alluvium (Typic Xerofluvents) and lacking any evidence of carbonate redistribution to those developed on Lower or Middle Pleistocene surfaces (provisionally classified as Petrocalcic Xerochrepts) and showing distinct petrocalcic horizons. X‐ray and electron optical analyses indicated a clear gradation in the relative contents of palygorskite and smectite clay minerals within this chronosequence. Palygorskite increased as smectite decreased in older soils.