Rare earth distribution and its correlation with clay mineralogy in the clay-sized fraction of Cretaceous and Pliocene sediments (central Portugal)

Prudencio, M. J.; Figueiredo, M. Ondina; Cabral, J. M. P.

doi:10.1180/claymin.1989.024.1.06

Cited by 46 publications

(17 citation statements)

References 5 publications

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“…The REE are released from primary minerals and taken up by the secondary phases during kaolinization. The REE are leached by local meteoric waters from the upper levels of the profiles and concentrated in deeper zones, probably in the form of complexes, or by mechanical transport of secondary phases (clay minerals and oxides) (cf., Prudencio et al, 1989). However, Ce has a different behavior, as it may be partly oxidized to Ce 4+ , which is retained in the upper levels of the soil profile relative to the other trivalent REE.…”

Section: Fig 5 Ternary Sio 2 /Al 2 O 3 /Total Oxides Diagram Of Ugamentioning

confidence: 99%

“…This accounts for the observed negative Ce anomalies displayed in the Buwambo kaolin samples. Although kaolinite accommodates the REE (Prudencio et al, 1989), and particularly the LREE (Nesbitt, 1979), a basic pH environment is also known to fractionate LREE-HREE, as the HREE are preferentially retained in solution, where they form soluble complexes (Cantrell and Byrne, 1987).…”

Section: Fig 5 Ternary Sio 2 /Al 2 O 3 /Total Oxides Diagram Of Ugamentioning

confidence: 99%

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The Buwambo kaolin deposit in central Uganda: Mineralogical and chemical composition.

2001

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Kaolin from the Buwambo deposit, located about 27 km north of Kampala (Uganda), has been analyzed for its mineralogical and chemical composition. The kaolin is derived from granite of the basement, which is exposed due to deeply weathered Buganda-Toro cover rocks. Kaolinite is the dominant mineral, with quartz and muscovite/illite as accessory minerals. Chemical data show that the kaolin is composed mainly of SiO 2 and Al 2 O 3 , with the other oxides being present in trace amounts. The depletion in Ti, Fe, Mn, Mg, Ca, Na, and K not only shows the extent of the kaolinization, but also gives Buwambo kaolin its almost white color. The kaolinization and weathering processes have enriched Ni and depleted other trace element contents in the Buwambo kaolin. The chondrite-normalized rare earth element (REE) patterns show enrichment in the light REEs, with a negative Ce anomaly. The REE pattern and the content of the other trace elements, show evidence of alteration and weathering processes related to kaolinization. The mineralogical and chemical compositions indicate that the kaolin is suitable for industrial use.

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Section: Fig 5 Ternary Sio 2 /Al 2 O 3 /Total Oxides Diagram Of Ugamentioning

confidence: 99%

Section: Fig 5 Ternary Sio 2 /Al 2 O 3 /Total Oxides Diagram Of Ugamentioning

confidence: 99%

The Buwambo kaolin deposit in central Uganda: Mineralogical and chemical composition.

2001

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“…Other studies within the study area broaching mineralogy and geochemistry of Cretaceous sediments were carried out by Prudêncio et al (1988Prudêncio et al ( , 1989.…”

Section: Introductionmentioning

confidence: 99%

Patterns of rare earth and other trace elements in Paleogene and Miocene clayey sediments from the Mondego platform (Central Portugal)

et al. 2015

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a b s t r a c tIn the present study the origin of clay deposits occurring in an inland platform, in central Portugal, was investigated by their mineralogical and chemical composition. The clay deposits, exploited for ceramic industry are composed of silt-clay facies, the Monteira Member and the Arroç a Member, which are assigned to the Coja Formation (Paleogene) and the Campelo Formation (Miocene), respectively. These clayey facies show almost compositional homogeneity, especially concerning texture. The mineralogical composition of the Monteira Member displays slightly higher content in smectite and interstratified clay minerals, which is supported by the chemical composition of samples analyzed. Both members present similar REE patterns, displaying an intense weathering record and little variation in the source area composition. Minor element geochemistry suggests low content in heavy minerals and transition metals. REE patterns and ratios of geochemical parameters support the dominant metasedimentary provenance, with a granite source contribution and also mature recycled sediments of continental origin. The study results' suggest that the clays of these two members have the same source in terms of lithology and recycled sediments from the Hesperian massif. During the deposition of the Arroç a Member, a major remobilization of the Monteira Member is suggested, explaining the geochemical similarity of both facies.

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“…These factors may influence the REE geochemistry of the soils. Prudencio et al (1989) inferred that REEs are adsorbed more readily onto kaolinite than other clay minerals. Under acidic conditions, kaolinite dissolution is enhanced by the formation of complexes between Al and humic substances (Viers et al 1997).…”

Section: Resultsmentioning

confidence: 98%

Abundance of rare earth elements in rice paddy soils from three regions of Sri Lanka

Chandrajith

Dissanayake

Tobschall³

2004

Paddy Water Environ

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Very few studies deal with the rare earth element (REE) content within paddy soil systems. This paper presents, for the first time, the distribution of REEs in paddy soils from three different regions in Sri Lanka. Seventy samples from the Kalutara and Kandy regions located in the Wet Zone and Anuradhapura region in the Dry Zone were selected for this study. ICP-MS measurements were performed on the soil samples to determine their respective REE concentrations. The sum content of all the REEs (SREE) in these three regions were 182, 186 and 132 mg/g, respectively. The mean concentrations for the 70 soil samples in g/g were 350.23 (Lu). The chondrite-normalized REE patterns of the paddy soils from the three study areas were similar, which may be a reflection of comparable parent materials. Kalutara soils, which are richer in organic matter and kaolinite, showed a higher lighter REE content and lower heavy REE content with a more pronounced negative Eu anomaly with respect to the other regions. Whilst this may be a result of subtle differences in soil parent materials, it could also reflect secondary processes related to clay mineral and organic matter adsorption of REEs in paddy soils

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Rare earth distribution and its correlation with clay mineralogy in the clay-sized fraction of Cretaceous and Pliocene sediments (central Portugal)

Cited by 46 publications

References 5 publications

The Buwambo kaolin deposit in central Uganda: Mineralogical and chemical composition.

The Buwambo kaolin deposit in central Uganda: Mineralogical and chemical composition.

Patterns of rare earth and other trace elements in Paleogene and Miocene clayey sediments from the Mondego platform (Central Portugal)

Abundance of rare earth elements in rice paddy soils from three regions of Sri Lanka

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