Genesis and Hardening of Laterite in Soils

Alexander, Lyle T.; Cady, John G.

doi:10.1097/00010694-196307000-00015

Cited by 57 publications

(43 citation statements)

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“…This result may at first indicate that unlike plinthite, petroplinthite is slightly more vulnerable to the action of distilled water (reduced environment) or to low-alkalinity solutions, close to neutrality, and unsusceptible to acid or highly alkaline solutions. Similar results were observed by Alexander and Cady (1962) in Sierra Leone, Africa, where it was found that the softest laterite was found near creeks, due to the higher availability of moisture and vegetation cover.…”

Section: Compressive Strength Of Plinthite and Petroplinthite Under Dsupporting

confidence: 87%

“…The great variability in compressive strength between immersion periods is related to the great natural variability observed in the composition of subsamples from a same soil horizon and to the impossibility of selecting subsamples with the same degree of purity because of their different stages of development, consistent with observations by Santos and Batista (1996) and Martins et al (2018). However, Alexander and Cady (1962) and Daugherty and Arnould (1982) claimed that the conditions required for the hardening of plinthic materials are extremely variable, particularly the amount of time required, in disagreement with the results of this study.…”

Section: Compressive Strength Of Plinthite and Petroplinthite Under Dsupporting

confidence: 81%

“…It is the result of subsurface accumulation of iron hydroxides, kaolinite, and quartz, which may undergo irreversible hardening and consequently be transformed into petroplinthite (Daniels et al, 1978;Gardi et al, 2014). Thus, petroplinthite is an extremely consolidated and firm material when moist and extremely hard when dry (Alexander and Cady, 1962;Santos et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Ferruginous crusts containing only Fe and Al oxides do not provide plants with nutrients and have low water retention capacity (Alexander and Cady, 1962). On the other hand, ferruginous crusts with kaolinite contain water and channels that can be penetrated by roots.…”

Section: Introductionmentioning

confidence: 99%

“…Some laterites contain encapsulated weathering minerals, such as micas and feldspars which, when ruptured, can provide nutrients. The presence of vegetation in lateritic areas is an important factor to reverse the hardening process of this material, which is caused by reduction and chelation with organic matter, by the mechanical action of roots, and mitigation of temperature and drought (Alexander and Cady, 1962). Coelho et al (2001) studied the development of nodular ferricretes (iron-rich crusts) in sandstone of the Bauru Group, and concluded that the cortex of the petroplinthic profiles was yellowish, suggesting dissolution and removal of hematite, favoring the presence of goethite.…”

Section: Introductionmentioning

confidence: 99%

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Reversibility of the Hardening Process of Plinthite and Petroplinthite in Soils of the Araguaia River Floodplain under Different Treatments

Martins

Santos

Oliveira

et al. 2018

Rev. Bras. Ciênc. Solo

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ABSTRACT:Although ferruginous materials occur frequently in soils of tropical regions, information about the reversal of the hardening process of these materials is scarce. This study assessed the influence of different chemical treatments and periods of immersion on the reversibility of the hardening process of plinthite and petroplinthite in soils of the Araguaia River plain. Soil samples were collected from the plinthic horizons in 0.10 m high and 0.15 m diameter PVC cylinders and divided into subsamples with a rock hammer. Homogeneous petroplinthite samples were also collected and broken into subsamples with a rock hammer. The plinthite and petroplinthite subsamples were subjected to five immersion treatments: distilled water, calcium carbonate solution, sodium hydroxide solution, sodium hydroxide solution + sodium hexametaphosphate, and acidic solution. The subsamples were immersed for 20, 40, 80, and 160 days. The dispersion and stability degrees and compressive strength in these subsamples were assessed. The wet aggregate stability test indicated no impact on the structural stability of plinthite and petroplinthite subsamples subjected to the treatment with different chemical agents, demonstrating the non-reversibility of the hardening process of these materials of the Araguaia River floodplain, under the studied conditions.

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Section: Compressive Strength Of Plinthite and Petroplinthite Under Dsupporting

confidence: 87%

Section: Compressive Strength Of Plinthite and Petroplinthite Under Dsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Reversibility of the Hardening Process of Plinthite and Petroplinthite in Soils of the Araguaia River Floodplain under Different Treatments

Martins

Santos

Oliveira

et al. 2018

Rev. Bras. Ciênc. Solo

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References

2012

Ecology and Management of Forest Soils

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Ferricretes in fluvial archives of a tropical iron province: Records of the Late Quaternary landscape dynamics in the Brazilian Atlantic Plateau

de Paula Barros,

de Oliveira,

Magalhães

et al. 2024

Earth Surf Processes Landf

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The occurrence of iron‐rich rocks in some areas makes possible the formation of duricrusts in positions from the relief tops to the slopes and valley bottoms, as is the case of the Quadrilátero Ferrífero (QF—‘Iron Quadrangle’) in the Brazilian Atlantic Plateau. This study aimed to analyse these materials in the Late Pleistocene fluvial archives of the QF to contribute to the understanding of the complex processes involved in the evolution of surface coverage in tropical regions. The results showed an essential external iron source for the Fe‐cemented alluvium, that is, they are ferricretes. Two ferricrete facies were identified: plate‐shaped and conglomeratic. They are characterised by the infilling of a primary porous system with crystalline and amorphous ferruginous phases or grain coatings by ferruginous materials. In plate‐shaped ferricretes, the size of the cemented grains differentiates the identified subtypes. Conglomeratic ferricretes can be subdivided into ferruginous and aluminous, and feature two types of cementing microstructures: septary and microlaminar. The results of the X‐ray diffraction analysis of the conglomeratic ferricretes highlight the strong presence of goethite (more common) and hematite. The chemical composition corroborated the mineralogical analysis, with the septa having an average iron‐rich composition. Aluminous conglomeratic ferricretes also occur and are the oldest in the area; their cement is composed mainly of gibbsite. Thus, it can be considered (i) a possible past source area of aluminous sediments or (ii) the in situ deferruginisation of a first level of ferricretes. A certain granulometric control in both ferricrete facies reinforces the importance of transport and deposition during ferricrete genesis. However, the cementing of sediments under supergene conditions and their microstructural variety suggest that their formation and evolution also occurred as a result of lateritic processes. Furthermore, the ferricretes revealed integration with the regional relief evolution, and the conglomeratic ones may be associated with lower rates of drainage incisions in some valleys.

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Genesis and Hardening of Laterite in Soils

Cited by 57 publications

References 0 publications

Reversibility of the Hardening Process of Plinthite and Petroplinthite in Soils of the Araguaia River Floodplain under Different Treatments

Reversibility of the Hardening Process of Plinthite and Petroplinthite in Soils of the Araguaia River Floodplain under Different Treatments

References

Ferricretes in fluvial archives of a tropical iron province: Records of the Late Quaternary landscape dynamics in the Brazilian Atlantic Plateau

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