Fibrous clay minerals in the soils of Namaqualand, South Africa: characteristics and formation

Singer, Arieh; Kirsten, W. F.A.; Bühmann, C.

doi:10.1016/0016-7061(94)00052-c

Cited by 49 publications

(21 citation statements)

References 23 publications

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“…Palygorskite has been reported to be a soil component worldwide, whereas the formation of sepiolite in soils is relatively rare because of its instability in soil [43,44]. The intense peak of sepiolite is not present in Fig.…”

Section: Mineral Compositionmentioning

confidence: 98%

Palygorskite in the Late Miocene Red Clay Sediment from the Chinese Loess Plateau and Its Paleoclimatic Implications

Xie

Qiu

Chen

et al. 2015

Springer Geochemistry/Mineralogy

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Palygorskite is the predominant component of the Red Clay sediment on the Chinese Loess Plateau. The morphological characteristics and microstructures of palygorskite in four sections of late Miocene Red Clay were investigated using power X-ray diffraction (XRD), scanning electron microscopy (SEM), and highresolution transmission electron microscopy (HRTEM). The XRD results suggest that the clay minerals in the Red Clay are mainly illite, kaolinite, chlorite, and palygorskite with smectite. Two types of palygorskite microtexture were observed in the Red Clay sediment: (1) relatively straight, fibrous crystals in bundles or intertwined aggregates or in matted, felted masses on other minerals and silky aggregates radiating from platy minerals; and (2) single crystals scattering among or coating detrital particles. Based on SEM investigations, the first aggregate is considered to be the major type of microtexture. The occurrence of this type of microtexture supports the hypothesis that palygorskite developed through pedogenesis of the red clay deposits. The authigenic palygorskites are thought to be formed through the transformation of existing aeolian mineral (e.g., smectite) and direct

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Section: Mineral Compositionmentioning

confidence: 98%

Palygorskite in the Late Miocene Red Clay Sediment from the Chinese Loess Plateau and Its Paleoclimatic Implications

Xie

Qiu

Chen

et al. 2015

Springer Geochemistry/Mineralogy

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“…Nevertheless, sepiolite was associated to mature calcretes of pedogenetic origin and their formation is related to calcite precipitation processes (Hay and Wiggins, 1980;Watts, 1980;Singer et al, 1995;Brock and Buck, 2005).…”

Section: Introductionmentioning

confidence: 99%

Fibrous-clay mineral formation and soil evolution in Aridisols of northeastern Patagonia, Argentina

et al. 2007

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“…Diagenetic formation of these compounds is more common: pedogenic sepiolite (e.g. Scholz, 1968a,b;Kautz and Porada, 1976;Watts, 1980;Netterberg, 1982;Botha and Hughes, 1992;Singer et al, 1995) and secondary silica (e.g. Smale, 1973;Summerfield, 1982Summerfield, , 1983McCarthy and Metcalfe, 1990;Nash et al, 1994a,b;McCarthy and Ellery, 1995;Nash and Shaw, 1998;Shaw and Nash, 1998) are common constituents of soils and duricrusts in many parts of southern Africa.…”

Section: Composition Of the Clay Fractionmentioning

confidence: 97%

The nature of calcareous deposits along pan margins in eastern central Namibia

Mees

2002

Earth Surf Processes Landf

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In a region along the western margin of the Kalahari in eastern Namibia and western Botswana, many pan basins have mainly calcareous deposits along part of their margins. These are typically lined by low vertical scarps. In Namibia, these pans are mainly located in dry river beds. The petrographical study of these deposits demonstrates that they consist of lacustrine sediments that have to a varying extent been affected by early-diagenetic processes and by the formation of late-diagenetic features.The original composition of the deposits ranges from highly calcareous sediments, typically with ostracod, diatom and charophyte remains, to entirely non-calcareous diatomites. The deposits generally show an upward increase in total carbonate content, which is mainly a synsedimentary feature. The early-diagenetic processes that affected the deposits include the formation of orthic siliceous nodules. At a later stage, secondary calcite enrichment occurred, leaving only the silica-impregnated sections unaffected. This enrichment partly accounts for the upward increase in total carbonate content in some profiles and often resulted in the development of a highly calcareous surface horizon. Sepiolite and amorphous silica that are part of the groundmass of the deposits may also partly have formed at this stage. Late-diagenetic features include various forms of secondary calcite and silica.This study of pan basins in eastern central Namibia indicates that a lacustrine rather than purely pedogenic origin should also be considered for calcareous deposits that commonly occur along pan margins in other parts of southern Africa.

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Fibrous clay minerals in the soils of Namaqualand, South Africa: characteristics and formation

Cited by 49 publications

References 23 publications

Palygorskite in the Late Miocene Red Clay Sediment from the Chinese Loess Plateau and Its Paleoclimatic Implications

Palygorskite in the Late Miocene Red Clay Sediment from the Chinese Loess Plateau and Its Paleoclimatic Implications

Fibrous-clay mineral formation and soil evolution in Aridisols of northeastern Patagonia, Argentina

The nature of calcareous deposits along pan margins in eastern central Namibia

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