Free Iron Sources in an Aquult-Udult Sequence from North Carolina

Daniels, R. B.; Gamble, E. E.; Buol, S. W.; Bailey, H. H.

doi:10.2136/sssaj1975.03615995003900020028x

Cited by 26 publications

(17 citation statements)

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“…13-8a) from the moist Highlands/Mistbelt region in southern Africa (Fig. 13-8b and c; Fitzpatrick, 1983) \vhich have distinct rinds consisting of higher amounts of Fe (20 to 30% Fe) than the interior weathered residuum (12)(13)(14)(15)(16)(17)(18)(19) suggests that they formed via polycyclic processes because the Fe in the rinds is largely goethite with lower Al substitution 04-18 mol % AIOOH) than the goethite in the interior material (20-27 mole % AIOOH). Moreover, the clay fraction in the matrix contains high AI-substituted goethites (25-30 mole % AIOOH) suggesting that it is in equilibrium with the current acid, freely drained, weathering environment.…”

Section: -44 Micro-pedological Scalementioning

confidence: 99%

Iron Compounds as Indicators of Pedogenic Processes: Examples from the Southern Hemisphere

Fitzpatrick

1988

Iron in Soils and Clay Minerals

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Section: -44 Micro-pedological Scalementioning

confidence: 99%

Iron Compounds as Indicators of Pedogenic Processes: Examples from the Southern Hemisphere

Fitzpatrick

1988

Iron in Soils and Clay Minerals

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“…Ferrimagnetics (magnetite and maghemite) in coastal plain soils are scarce, but quantifying them or other forms of soil iron may prove useful for predicting the ineffectiveness of MS below certain thresholds. Daniels et al (1975) found little relationship between various types of selective dissolutions for iron (acid ammonium oxalate, Na dithionite, HCl) and the amount of magnetic heavy minerals in coastal plain soils determined by standard (followed by magnetic) fractionation. Likewise, if MS was shown to have a similarly poor correlation to common soil iron analyses, the conclusion could be made that ferrimagnetics are also the primary contributor to the MS of coastal plain soils.…”

Section: Methodsmentioning

confidence: 99%

“…The coastal plain receives approximately 50 inches of precipitation annually and is classified as humid subtropical, with an average annual temperature of 70°F (Ceryak et al, 1983). Coastal plain soils typically have been exposed to long‐term weathering, burial, and erosion (Daniels et al, 1975). Aluminosilicates containing Fe (e.g., biotite) are typically weathered on deposition, and the Fe forms secondary iron oxides, primarily lepidocrocite (γ‐FeOOH), maghemite, and goethite (α‐FeOOH).…”

Section: Soil Parent Materials and Climatementioning

confidence: 99%

Using Magnetic Susceptibility to Delineate Hydric Soils in Southeastern Coastal Plain Soils

et al. 2007

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Identifying hydric soil boundaries is one component in delineating jurisdictional wetlands. Evaluating hydric soil field indicators using borings along transects is an invasive and arduous task. Magnetic susceptibility (MS) has been used successfully as a geophysical method for determining hydric soil boundaries by detecting a drop in soil magnetism when iron minerals mobilize or are recrystallized in alternating reducing and nonreducing conditions. Magnetic suseptibility has not, however, been fully evaluated in the soils of the southeastern coastal plain, where iron minerals are uncommon and a substantial amount of wetland delineation work is performed. Five relatively pristine and two disturbed wetland sites in northern Florida were rapidly evaluated by recording uncorrected volumetric MS measurements (n = 12 hydric; n = 12 nonhydric) on 1 by 7 yd transect grids centered on the hydric soil boundary as determined by field indicators. At the more sensitive “×0.1” instrument setting, instrument drift obscured any true differences in the populations of hydric and nonhydric MS values. Two additional sites in southeastern Georgia and two of the original sites were selected for a more intensive survey (n = 30 random hydric; n = 30 random nonhydric) volumetric MS measurements recorded inside a 3 by 20 yd transect block centered on the hydric soil boundary. Values were air‐corrected for temperature drift, and the hydric and nonhydric populations were compared. All four sites showed significant (P < 0.004) differences in both population means and medians. However, the necessity for air correction, statistical analysis, and the lack of a unique MS value separating hydric and nonhydric populations make the use of this technique for delineating the precise hydric soil boundary impractical in this region. Mass specific MS measurements of the surface soils at two sites had a marginal correlation (R2 = 0.78) with total and ammonium oxalate extractable iron, and trace amounts of iron minerals—most likely maghemite and goethite—were magnetically separated from filter residue and unaccounted for in the total iron analysis. This sporadic occurrence of ferrimagnetics has an overriding but difficult‐to‐quantify influence on the effectiveness of this method in the southeastern coastal plain.

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“…Seqüências com horizontes similares foram estudadas em outros países como na Guiana, Austrália, Índia e são consideradas pelos autores como a evolução pedogenética típica das regiões tropicais (Daniels et al, 1975, Williams e Coventry, 1979, Fritsch e Fitzpatrick, 1994, Peterschmitt et al, 1996, Melfi et al, 1999.…”

Section: Lateral Entre Os Horizontes Dos Solos Do Platô E Da Depressãounclassified

Expansão dos solos hidromórficos e mudanças na paisagem: um estudo de caso na região Sudeste da Amazônia Brasileira

Rosolen

Herpin

2008

Acta Amaz.

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ResumoNa região sudoeste da Amazônia brasileira, foi realizado um estudo detalhado da cobertura pedológica em uma toposseqüência representativa da paisagem regional, caracterizada por baixos platôs com depressões topográficas. Os resultados indicaram que os processos pedogenéticos podem ser considerados como responsáveis pelo rebaixamento topográfico e mudanças da paisagem natural. O principal fator envolvido neste processo de transformação é a expansão remontante da hidromorfia, a partir das depressões topográficas desenvolvidas nas superfícies dos platôs. Este processo envolve transformações e degradações internas na matriz do solo acarretando em modificações na estrutura, composição química e diminuição do volume do solo.PalavRas-chave: Depressão topográfica; Solo laterítico; Laterita hidromórfica; Rebaixamento topográfico. Expansion of hydromorphic soils and landscape changes: a case study in the Southwestern Brazilian Amazon abstRactIn the Southwestern Brazilian Amazon, a detailed study on the pedological cover of a representative toposequence for the region, characterized by lowered plateaus with topographic depressions, was carried out. The results indicated that pedogenic processes can be considered to be responsible for topographic smoothing and changes of the natural landscape. The main factor involved in this transformation process represents the upwards expansion of hydromorphic soil conditions from the topographic depressions developed in lower parts of the plateaus. This process includes internal transformations and degradations of the soil matrix leading to changes in soil structure, chemical composition and, diminishment of the original soil volume.

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Free Iron Sources in an Aquult-Udult Sequence from North Carolina

Cited by 26 publications

References 0 publications

Iron Compounds as Indicators of Pedogenic Processes: Examples from the Southern Hemisphere

Iron Compounds as Indicators of Pedogenic Processes: Examples from the Southern Hemisphere

Using Magnetic Susceptibility to Delineate Hydric Soils in Southeastern Coastal Plain Soils

Expansão dos solos hidromórficos e mudanças na paisagem: um estudo de caso na região Sudeste da Amazônia Brasileira

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