Effects of parent material and climate on the magnetic susceptibility of Saskatchewan soils

. 2005. Magnetic susceptibility of soil separates of Gleysolic and Chernozemic soils. Can. J. Soil Sci. 85: 233-244. The major horizons of Gleysolic and Chernozemic soils and the underlying deep till of five cores were separated into sand-, silt-and clay-sized fractions. Pedogenesis increased the ranges of magnetic susceptibility (χ) and oxalate (Feo) and dithionite-citrate extractable (Fed) iron in bulk samples and size separates of the A, B and IC horizons compared to the deep till. In the A, B and IC horizons the relationships between χ of the bulk (< 2 mm diameter) soil and χ of the sand and silt fractions was much stronger than in the deep till. Generally, χ of the clay was much lower than that of the coarser fractions, whose χ was similar or slightly larger than that of the bulk samples, except for two buried, burned horizons. Treatment of the sand fraction of 15 soils with dithionite-citrate to remove pedogenic ferrimagnetics showed that the latter decreased in the order: burned, buried horizons > gleysolic and chernozemic A horizons > gleysolic B horizons > IC horizons. The low χ of the gleysolic horizons cannot be attributed to a decrease in pedogenetically formed ferrimagnetics; they must have lost part of their inherited ferrimagnetics, possibly sand-sized magnetite. En général, l'argile a une valeur χ nettement plus faible que les fractions à plus grosse granulométrie, dont la valeur χ est similaire ou légèrement plus élevée que celle des échantillons non fractionnés, sauf pour deux horizons brûlés et enfouis. Lorsqu'on traite la fraction sableuse des 15 sols avec du citrate de dithionite en vue d'éliminer les particules ferromagnétiques issues de la pédogenèse, on remarque que la concentration de ces dernières diminue de la manière suivante : horizons brûlés et enfouis > horizons A des gleysols et tchernozioms > horizons B des gleysols > horizons IC. La faible valeur χ des horizons des gleysols ne peut être attribuée à une baisse du ferromagnétisme résultant de la pédogenèse; les horizons doivent avoir perdu une partie de leur ferromagnétisme sans doute sous forme de magnétite de la granulométrie du sable.

Section: Methodsmentioning

confidence: 99%

Magnetic susceptibility of soil separates of Gleysolic and Chernozemic soils

Jong¹,

Heck²,

Ponomarenko³

2005

“…Magnetic susceptibility of all samples was determined with a Bartington MS-2D meter at low (0.47 kH, χ lf ) and high (4.7 kH, χ hf ) frequency as described by de Jong et al (2000a). Frequency dependence of the magnetic susceptibility was expressed as:…”

Section: Methodsmentioning

confidence: 99%

“…The magnetic susceptibility of soils depends on the nature of the parent material, and the physical, chemical and biological weathering processes. Welldrained soils generally show increased χ in the A horizons (Dearing et al 1985;Fine et al 1989;Maher 1998;de Jong et al 2000a), while the solum of poorly-drained soils has reduced χ (Dearing et al 1985;Williams and Cooper 1990;de Jong et al 1998;Maher 1998;Grimley and Vepraskas 2000). In Saskatchewan soils χ was found to increase with sand content (de Jong et al 1998(de Jong et al , 2000a(de Jong et al , 2000b and to decrease with increasing Feo/Fed ratio, but was not affected by total Fe content.…”

mentioning

confidence: 99%

Magnetic susceptibility of Gleysolic and Chernozemic soils in Saskatchewan

Jong¹

2002

In Saskatchewan, Gleysolic and Chernozemic soils often are found close to each other in hummocky terrain. Magnetic susceptibility (χ) is known to be reduced in poorly drained soils compared to well-drained soils, and this study investigated the use of χ as an accessory criterion for identifying Gleysols. Archived soil samples from an area near Saskatoon were analyzed for χ and sand content, and where necessary for organic and inorganic C and oxalate (Feo) and dithionite (Fed) extractable iron. The lowest χ values were found in Humic Luvic Gleysols and the highest in Dark Brown Chernozems; Rego and Orthic Gleysols and Rego Humic Gleysols had χ values that overlapped those of the Dark Brown Chernozems. Within the upper 50 cm of the profile, all Gleysols except the Rego Humic Gleysol had at least one horizon with %chi; less than 150 × 10-9m3kg-1. The χ of the A and B horizons was negatively correlated to their Feo/Fed ratios, and not correlated to their sand content. The χ of the deep tills was positively correlated to sand content, and not correlated to Feo/Fed ratio. It appears that χ may be as useful as the Feo/Fed ratio for assisting in classifying Gleysols. Key words: Magnetic susceptibility, Gleysols, Chernozems, Feo, Fed, CaCo3

“…This transformation is enhanced in soils with restricted drainage, where the development of anaerobic conditions increases the solubility of Fe. In the case of magnetite, the transformation results in a considerable decrease of MS (Maher 1986(Maher , 1998Williams 1992;de Jong et al 2000;Grimley et al 2004). In contrast, the formation of secondary oxides from other Fe-bearing minerals (such as silicates) would increase soil MS. Pedogenic Fe minerals generally occur as SP or SSD size grains (Maher and Taylor 1989;Maher 1998), but they can be associated with all soil particle-size separates.…”

mentioning

confidence: 99%

“…Though the MS of incipient soils closely reflects that of the parent material, divergence occurs as pedogenesis proceeds Fine et al 1992;Feng and Johnson 1995;de Jong et al 2000). Primary Fe-bearing minerals (magnetite, biotite, and pyrite) are thermodynamically unstable in soils, eventually being transformed to secondary minerals, typically Fe oxides (goethite and hematite).…”

mentioning

confidence: 99%

The magnetic susceptibility of soils in Kohgilouye, Iran

Owliaie¹,

Heck²,

Abtahi³

2006

. 2006. 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 (Kohgilouye Province). Alfisols, in the eastern and northern parts, contained more pedogenic (citrate dithionite extractable) Fe (up to 60 g kg -1 on a minerogenic basis; 70% of total Fe, as determined by lithium tetraborate fusion) and poorly crystalline Fe (up to 6 g kg -1 ammonium oxalate extractable) than the Inceptisols in the southern parts. Soil MS (χ lf ) ranged from 5 to 120 × 10 -8 m 3 kg -1 , with A horizons exhibiting greater values than B horizons, and Alfisols higher than other soils. Pedogenic enhancement of χ lf corresponded with preferential leaching of diamagnetics (primarily carbonates), as well as weathering of primary paramagnetics and neoformation of antiferromagnetics. Frequency dependence of MS (χ fd ), indicating ultrafine superparamagnetics, followed trends similar to χ lf . Sequential heating of well-drained samples, from 25 to 500°C, resulted in enhancement of χ (average of 21%), attributed to the conversion of antiferromagnetics to ferrimagnetics; between 500 and 700°C, χ typically decreased (average of 15%). The χ fd of well-drained soils increased by an average of 5.3 percentiles by 700°C. Gleysolic soils exhibited less weathering (<51% of total Fe), higher proportions of poorly crystalline Fe (>0.15), lower χ lf (<25 × 10 -8 m 3 kg -1 ) and χ fd (<2%), as well as greater average enhancements of χ lf (265% at 500°C) and χ fd (8.4 percentiles at 700°C) on heating.Key words: Calcareous, iron oxides, citrate dithionite, ammonium oxalate, frequency dependence, thermal enhancement Owliaie, H. R., Heck, R. J. et Abtahi, A. 2006. Sensibilité magnétique des sols de Kohgilouye, en Iran. Can. J. Soil Sci. 86: 97-107. Les auteurs ont examiné la sensibilité magnétique (SM) et le fer de plusieurs sols reposant sur une assise calcaire, reflet des conditions climatiques et classes de drainage qu'on retrouve habituellement dans le sud-ouest de l'Iran (province de Kohgilouye). Les alfisols des parties est et nord de la région contenaient plus (jusqu'à 60 g par kg sur la base minérogénique; 70 % du Fe total mesuré par fusion avec du tétraborate de lithium) de Fe pédogénétique (extractible au citrate de dithionite) et de Fe peu cristallin (jusqu'à 6 g par kg extractible à l'oxalate d'ammonium) que les inceptisols de la partie sud. La SM du sol (χ lf ) variait de 5 à 120 × 10 -8 m 3 par kg, les valeurs étant plus élevées dans l'horizon A que dans l'horizon B et dans les alfisols que les sols d'un autre type. L'amélioration de la χ lf par pédogenèse vient principalement de la lixiviation préférentielle des substances diamagné-tiques (des carbonates surtout) ainsi que de l'altération des substances paramagnétiques primaires et de la néoformation de substances antiferromagnétiques. La fonction de la fréquence de la SM (χ fd ), signe...