Title: The magnetic susceptibility of soils in Kohgilouye, Iran

Author(s): Owliaie HR, Heck RJ, Abtahi A

Source: CANADIAN JOURNAL OF SOIL SCIENCE 86 (1): 97-107 FEB 2006

Document Type: Article

Language: English

Abstract: The magnetic susceptibility of soils in Kohgilouye, Iran. Can. J. Soil Sci. 86: 97-107. Soil magnetic susceptibility (MS) and Fe were examined for several soils on calcareous parent material. reflecting key climatic conditions and drainage classes in southwestern Iran (Koligilouye Province). Alfisols, in the eastern and nor-them parts, contained more pedogenic (citrate dithionite extractable) Fe (up to 60g 2 kg(-1) on a minerogenic basis: 70% of total Fe, as determined by lithium tetraborate fusion) and poorly crystalline Fe (up to 6 a kg(-1) ammonium oxalate extractable) than the Inceptisols in the southern parts. Soil MS (chi(If)) ranged from 5 to 120 x 10(-8) m(3) kg(-1), with A horizons exhibiting greater values than B horizons. and Alfisols higher than other soils. Pedogenic enhancement of chi(If) corresponded with preferential leaching of diamagnetics (primarily carbonates), as well as weathering of primary paramagnetics and neoformation of antiferromagnetics. Frequency dependence of MS (chi(fd)), indicating ultrafine superparamagnetics, followed trends similar to chi(If). Sequential heating of well-drained samples, from 25 to 500 degrees C, resulted in enhancement of chi (average of 21%), attributed to the conversion of antiferromagnetics to ferrimagnetics: between 500 and 700 degrees C. chi typically decreased (average of 15%). The chi(fd) of well-drained soils increased by an average of 5.3 percentiles by 700 degrees C. Gleysolic soils exhibited less weathering (< 51% of total Fe). higher proportions of poorly crystalline Fe (> 0.15), lower chi(If) (< 25 x 10(-8) m(3) ka(-1)) and Xrd (< 2%), as well as greater average enhancements of chi(lf) (265% at 500 degrees C) and chi(fd) (8.4 percentiles at 700 degrees C) on heating.

Author Keywords: calcareous; iron oxides; citrate dithionite; ammonium oxalate; frequency dependence; thermal enhancement

KeyWords Plus: PALEOCLIMATIC IMPLICATIONS; CHINESE LOESS; IRON; DITHIONITE; CLIMATE; OXIDES; ORIGIN; USA

Addresses: Owliaie HR (reprint author), Shiraz Univ, Dept Soil Sci, Fac Agr, Shiraz, Iran
Shiraz Univ, Dept Soil Sci, Fac Agr, Shiraz, Iran
Univ Guelph, Dept Land Resource Sci, Guelph, ON N1L 1M4 Canada

E-mail Addresses: rheck@uoguelph.ca

Publisher: AGRICULTURAL INST CANADA, 280 ALBERT ST, SUITE 900, OTTAWA, ONTARIO K1P 5G8, CANADA

Subject Category: AGRICULTURE, SOIL SCIENCE

IDS Number: 066AP