Properties and Classification of Montmorillonite-Rich Hapludults in the Alabama Coastal Plains

Karathanasis, A. D.; Hurt, G. W.; Hajek, B. F.

doi:10.1097/00010694-198608000-00003

Cited by 8 publications

(3 citation statements)

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“…The soil pH ranged from strongly (LD, 5.32) to moderately acidic (CC, 5.69, and GB, 5.52) ( Table 2). In all soils, the CEC was low (6.8-12.3 cmol^, kg"'), as is typical of Ultisols (Kang et al, 1999;Karathanasis et al, 1986;Ludwig et al, 2001). Calcium was the dominant exchangeable cation in all soils.…”

Section: Results and Discussion Physicochemical Characterization Of Smentioning

confidence: 80%

Role of Natural Nanoparticles in Phosphorus Transport Processes in Ultisols

Rick

Arai

2011

Soil Science Soc of Amer J

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Labile P is a well-recognized nonpoint sourec pollutant in agroecosystems. Predicting the fate and transport of P in watershed systems is critical in protecting water quality. In this case study, we investigated the role of soil nanoparticles in P release in South Carolina agricultural soils. Batch desorption experiments were coupled with scanning and transmission electron microscopy (EM) and x-ray absorption spectroscopy (XAS) to better assess the reactivity of soil nanoparticles. The surface soils contained a total P concentration of 260 to 940 mg kg" ', approximately 40 to 60% of which was ammonium oxalate extractable R The 30-d desorption experiments showed that P desorption was initially rapid, followed by a slow continuous release at pH 5.5 and 7. It was generally not correlated with the release of soil nanoparticles (operationally defined as 10-200 nm). Phosphorus was not readily retained on these nanoparticles at pH 4 to 7. These nanoparticles were rich in Si and S, and coated with Fe and C and trace amounts of P, Ca, Na, Mg, and Al. The EM images of nanoparticle morphology showed C-associated globular formations as well as assembled platelets and spherical nanoparticles. The colloid-and nanoparticlefaeilitated P release has often been suggested as one of the important pathways for P transport in the soil-water environment. This study presents a new aspect of nanoparticle reactivity in the soil environment, however: nanoparticles do not always contribute to P transport processes.

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Section: Results and Discussion Physicochemical Characterization Of Smentioning

confidence: 80%

Role of Natural Nanoparticles in Phosphorus Transport Processes in Ultisols

Rick

Arai

2011

Soil Science Soc of Amer J

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“…In any case, smectite can apparently persist over long periods of time in some acidic (pH 4–5) soils (e.g. Karathanasis et al ., 1986; Mason et al ., 1994).…”

Section: Smectite Alterationmentioning

confidence: 99%

Deformation structures and an alteration zone linked to deposition of volcanogenic sulphate in an ancient playa (Oligocene of Nebraska, USA)

et al. 2005

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Historic, sulphur-rich volcanic eruptions have altered global climate for as much as five years, and much larger events are known from the geologic record. At Scotts Bluff, Nebraska, Early Oligocene strata of the lower Arikaree Group contain a tephra bed with abundant calcite pseudomorphs after gypsum. Previous work has shown sulphate from the pseudomorphs in this tephra bears a high 17 O anomaly indicative of oxidation of sulphur gases by ozone or hydrogen peroxide in the atmosphere. Possible sources of the tephra were caldera eruptions at about 28 Ma in the San Juan volcanic field of southwestern Colorado (500 km SW of the study site) and the eastern Great Basin (1000 km WSW). The present sedimentological study shows that tephra and volcanogenic sulphate were deposited and preserved within a small, surfacedischarging playa that developed on the irregular upper surface of aeolian siltstones of the subjacent White River Group. Sulphate solutions (including perhaps sulphuric acid) percolated downward within the vadose zone, dissolving early formed smectite cement within underlying volcaniclastic sandstones, reddening these rocks along an irregular alteration front. Preserved fine-scale stratification within the sandstones precludes the possibility that reddening took place during pedogenesis. Displacive growth of gypsum at the playa centre folded tephra beds and forced tephra into underlying sandstones, forming elongate cones. The large mass fraction of gypsum (now replaced by calcite) in the playa sediments suggests a huge, long-distance delivery of sulphate aerosols. Some of the sulphate and tephra may have come from the same eruption, or the fine-grained tephra may simply have aided preservation of dry-fog sulphate derived from an unrelated, effusive eruption of lava.

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“…Thus, Kantor & Schwertmann (1974) found that smectite increased with depth in some Kenyan Humults where it apparently formed as an initial weathering product of basic igneous rocks only to decompose in the surface horizons. Smectitic Ultisols have been more extensively studied in the USA where they may be developed upon smectite-rich shales, for example in the Alabama Coastal Plains (Karathanasis et al, 1986) and in Texas (Carson & Dixon, 1972). The above examples illustrate that Ultisol smectites are in the main inherited from suitable parent materials or may form, often ephemerally, through neoformation processes at the base of the profile.…”

Section: Smectite Mineralsmentioning

confidence: 99%

The origin and formation of clay minerals in soils: past, present and future perspectives

Wilson¹

1999

Clay miner.

403

202

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The origin and formation of soil clay minerals, namely micas, vermiculites, smectites, chlorites and interlayered minerals, interstratified minerals and kaolin minerals, are broadly reviewed in the context of research over the past half century. In particular, the pioneer overviews of Millot, Pedro and Duchaufour in France and of Jackson in the USA, are considered in the light of selected examples from the huge volume of work that has since taken place on this topic. It is concluded that these early overviews may still be regarded as being generally valid, although it may be that too much emphasis has been placed upon transformation mechanisms and not enough upon neoformation processes. This review also highlights some of the many problems pertaining to the origin and formation of soil clays that remain to be resolved.

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Properties and Classification of Montmorillonite-Rich Hapludults in the Alabama Coastal Plains

Cited by 8 publications

References 0 publications

Role of Natural Nanoparticles in Phosphorus Transport Processes in Ultisols

Role of Natural Nanoparticles in Phosphorus Transport Processes in Ultisols

Deformation structures and an alteration zone linked to deposition of volcanogenic sulphate in an ancient playa (Oligocene of Nebraska, USA)

The origin and formation of clay minerals in soils: past, present and future perspectives

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