Facies Problems of Boehmitic and Diasporitic Bauxites

Valeton, Ida

doi:10.1016/s0070-4571(08)70535-1

Cited by 20 publications

(33 citation statements)

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“…Each •nineral formed during intermediate stages can be weathered to the next stage by percolation of water across a wide range of pH values (•4-9). This sequence of weathering has been observed in numerous basaltic, marie, and ultramarie sequences and in laboratory studies [e.g., Seelye et al, 1938;Hanlon, 1944;Sherman, 1949;Carroll and Woof 1951;Jackson et al, 1952;Butler, 1954;Millot and Bonifas, 1955;Sherman and Uehara, 1956;Tiller, 1958;Sherman and Ikawa, 1959;Cottens, 1961;Coleman, 1962;Loughnan, 1962;Carroll and Hathaway, 1963;Keller, 1964;Valeton, 1972;Brigatti, 1983;Carroll, 1970;Maksimovi• 1976;Siever and Woodford, 1979;Nahon and Colin, 1982;Nahon et al, 1982;Kodama et al, 1988]. When volcanic glass or tuff is the parent rock, palagonite is co•mnonly the intermediate weathering product [Bates, 1962;Hay andlijima, 1968].…”

Section: Formation Conditions and Stability Of Diasporementioning

confidence: 58%

“…The formation of AI monohydrates such as diaspore and bOhmite from AI trihydrates such as gibbsitc is dependent on the vapor pressure of water, with low pressures favoring the former phases [Kennedy, 1959;Wayman, 1963]. Diaspore has also been found to form directly from the breakdown of clay minerals [Allen, 1935;Kennedy, 1959] as well as from the dehydroxylation of bOhmite in areas with "opti•num" drainage [Valeton, 1972] and conversion from gibbsitc [Allen, 1935]. h•creasing temperature also results in increasing rates of dissolution of most elements, but this is not a necessary condition if enough time is available tbr percolation and leaching to occur.…”

Section: Formation Conditions and Stability Of Diasporementioning

confidence: 99%

“…While the conditions required to form A1 hydroxides are well understood, the phase relationships among the different minerals in this group (gibbsitc, b6hmite, and diaspore) are somewhat uncertain, largely due to the slow kinetics of transformation at Earth surface temperatures and pressures. Measurable conversions are generally not reproducible in the laboratory without the use of seed crystals [e.g., Valeton, 1972].…”

Section: Formation Conditions and Stability Of Diasporementioning

confidence: 99%

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Diaspores and related hydroxides: Spectral‐compositional properties and implications for Mars

Cloutis¹,

Bell²

2000

J. Geophys. Res.

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Abstract. Differences in spectral reflectance properties (0.3-26 •tm) of a suite of metal hydroxides (gibbsite, bohmite, diaspore, goethite, and manganite) have been found to be a function of both structural and compositional differences between these minerals. The properties of the O-H stretching fundamental bands in particular can be used to identify the presence of these minerals and to discriminate isostructural and heteromorphous species. This is due to the fact that the O-H stretching fundamental bands are very intense in these minerals and occur at longer wavelengths than those of other minerals, and also due to the fact that these metal hydroxides lack strong absorption bands at shorter wavelengths. In the case of dimorphous minerals such as bohmite (¾-A10(OH)) and diaspore (tx-A10(OH)), differences in the wavelength positions of O-H stretching fundamental bands can be of the order of 0.1-0.3 [tm. Reflectance spectra of metal hydroxide-beating "ores" (bauxites) and impure samples indicate that accessory phases, in particular iron-beating minerals, have a more pronounced effect on spectral reflectance toward shorter wavelengths. Intimate mixtures of diaspore + orthopyroxene indicate that diaspore abundances as low as 5 wt % (or less) can be detected by the appearance of characteristic absorption bands at 3.33 and 3.41 •tm. This finding has particular relevance to the study of near-infrared spectra of Mars, in that the conditions which favor diaspore formation on the Earth may have also been prevalent early in Mars' history. If diaspore did form on Mars in the past, it is likely to have persisted to the present.

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Section: Formation Conditions and Stability Of Diasporementioning

confidence: 58%

Section: Formation Conditions and Stability Of Diasporementioning

confidence: 99%

Section: Formation Conditions and Stability Of Diasporementioning

confidence: 99%

See 1 more Smart Citation

Diaspores and related hydroxides: Spectral‐compositional properties and implications for Mars

Cloutis¹,

Bell²

2000

J. Geophys. Res.

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“…Therefore, the origin of the precursor bauxite can be interpreted even if it is somewhat reworked. Maximum possible aluminium enrichment, pisolite formation and formation of gibbsite can occur under extreme leaching conditions in a well-drained system (Valeton, 1972;Schaefer et al, 2002;Simas et al, 2005). Like gibbsite, kaolinite formation is indicative of a leaching regime that is very effective in removing silicon and developing mature soil profiles in a welldrained system (Mutakyahwa et al, 2003;Horbe & Peixoto, 2006).…”

Section: Oxisolmentioning

confidence: 99%

Palaeosols in early Himalayan foreland basin sequences demonstrate latitudinal shift‐related long‐term climatic change

et al. 2009

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The Palaeogene sedimentary record in the Himalayan foreland basin contains palaeosols that are interpreted as reflecting changes in climate through time with the passage of the Indian Plate from the equator to 30° N latitude. To understand spatial and temporal variation in the occurrence of diagnostic palaeosol types, 12 exposed stratigraphic sections were investigated and studied in detail using petrographic and geochemical techniques, including scanning electron microscopy and X‐ray mineralogy. Oxisol (bauxite) is a karst bauxite that occurs in crudely bedded and laminated forms. It contains gibbsite, goethite and kaolinite and shows chemical index of alteration values close to 100, demonstrating intense weathering. No gradual change in the concentrations of trace and rare earth elements is recorded. However, their behaviour suggests that the Oxisol was produced by weathering of basalt under a warm and humid climate. Histosol (coal), found stratigraphically higher than Oxisols, contains woody structures dominated by vitrinite maceral. The Histosol is interpreted as having originated from an undisturbed peat developed in a swamp of high tree density under wet tropical climatic conditions. Up‐section, calcrete profiles of stages 3 and 4, containing rhizoliths, pellets, filamentous calcite and Microcodium, have developed by pedogenic processes. Large negative stable carbon (−8·5‰ to −11·2‰) and oxygen isotope values (−8·5‰ to −12·6‰) suggest that the studied calcretes formed under the influence of meteoric water and soil organic matter in dry sub‐tropical climatic conditions. The formation of Oxisol in a warm and humid climate was possible in the equatorial region when part of the Indian subcontinent was close to the equator. The coal developed under a humid climate when the northern tip of the Indian subcontinent reached the intertropical convergence zone, while the pedogenic calcrete formed once the sub‐tropical climatic zone was reached. Hence, it is suggested that these palaeosols formed in different climatic zones during northward drift of the Indian plate and that the drift brought them to their present positions between 30° N and 35° N within the sub‐tropical climatic zone.

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“…For these reasons, aluminosilicates such as kaolinite and bauxite are popular raw materials for proppant fabrication. 5,6 Previous studies on bauxite-derived proppants have revealed that their microstructures and phase assemblages are susceptible to change during extended thermal treatment. 3 Similar observations are expected in proppants-derived from kaolinite.…”

Section: Materials Selection and Experimental Proceduresmentioning

confidence: 99%

Strength Enhancement of Aluminosilicate Aggregate Through Modified Thermal Treatment

Luscher

Hellmann

Scheetz

et al. 2006

Int J Applied Ceramic Tech

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Commercial aluminosilicate aggregates derived from kaolinite and bauxite were evaluated for various physical and mechanical properties. Suites of thermal treatments based on known phase relationships were performed, resulting in significant modification of microstructural and crystalline phase evolution. These structural changes were evaluated and rationalized via scanning electron microscopy and X‐ray diffraction, respectively. Subsequent measurement of mechanical strengths by diametral compression and density by gas pycnometry indicated increases in overall strengths (up to 24%) at a comparable densities (approximately 2.8 g/cm3) in kaolinite‐derived aggregates. Results of this study are being used to drive processing modifications to achieve higher specific strength in aluminosilicate‐derived aggregates.

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Facies Problems of Boehmitic and Diasporitic Bauxites

Cited by 20 publications

References 1 publication

Diaspores and related hydroxides: Spectral‐compositional properties and implications for Mars

Diaspores and related hydroxides: Spectral‐compositional properties and implications for Mars

Palaeosols in early Himalayan foreland basin sequences demonstrate latitudinal shift‐related long‐term climatic change

Strength Enhancement of Aluminosilicate Aggregate Through Modified Thermal Treatment

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