Rare earth elements in gneiss regoliths in southern Minas Gerais, Brazil

Gomes, Edilene Pereira; Guerra, Adriano Ribeiro; Azevedo, Antônio Carlos de

doi:10.1590/1678-992x-2019-0190

Cited by 3 publications

(1 citation statement)

References 43 publications

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“…According to the Chinese Environmental Monitoring Station (1990), the background values in soils are La 41.2, Ce 95.5, and Nd 30.5 (in mg kg −1 ). Pereira et al (2019) reported the following values (mg kg −1 ) for a soil developed in Brazil for the A and C horizons, respectively: La (4.3/12.6), Ce (9.3/15.9), Nd (3.3/12.2), while in another profile, they quoted the following values: La (121.3/67.3), Ce (223.5/154.5), Nd (96.0/60.9). These horizons are therefore clearly different.…”

Section: Ree Concentrationsmentioning

confidence: 99%

Occurrence of some rare earth elements in vineyard soils under semiarid Mediterranean environment

Jiménez‐Ballesta

Bravo

Ortíz-Villajos

et al. 2022

Environ Monit Assess

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A comprehensive investigation has been carried out into the concentrations of a range of REEs (neodymium Nd, cerium Ce, lanthanum La, yttrium Y, scandium Sc) in soils of vineyards belonging to the protected denomination of origin (PDO) Valdepeñas (Central Spain). The mean concentrations (expressed in mg kg−1) are Ce 70.6, Nd 32.9, La 36.2, Y 21.6, and Sc 13.7 in surface horizons (Ap), while in subsurface horizons (Bt or Bw and some Ck), the values are Ce 67.6, Nd 31.8, La 34.4, Y 19.6, and Sc 13.9. The relative abundance in these soils is Ce > La > Nd > Y > Sc in both the surface and subsurface horizons. These values are close to, or slightly higher than, the regional levels but similar to national and global averages, although relatively high values have been detected at certain sampling points. Another aim was to explain the spatial variations in these elements within the territory under study. It was found that the spatial variations are due to the nature of the parent materials and the pedogenetic processes, although the sparse spatial distribution patterns with prominent anomalies are interpreted arising from anthropogenic sources (fertilization). However, these anomalies did not present any environmental risk in the studied zone.

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Section: Ree Concentrationsmentioning

confidence: 99%

Occurrence of some rare earth elements in vineyard soils under semiarid Mediterranean environment

Jiménez‐Ballesta

Bravo

Ortíz-Villajos

et al. 2022

Environ Monit Assess

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Mineralogical and Elemental Trends in Regolith on Historically Managed Sites in the southeastern United States Piedmont

Schroeder

Austin

Thompson

et al. 2022

Clays and clay miner.

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The deep regolith of the southeastern United States has undergone rapid erosion in the last two centuries due to intensive agricultural practices, which has altered the landscape and its inherent fertility. Parent material, landscape position, and land use are important factors in controlling the mineral and elemental composition of soil profiles. Independent quantitative X-ray diffraction (QXRD) and whole-rock chemical analysis of eight weathering profiles agreed well and allow mineral reaction pathways to be constrained as particles are conveyed in the subsurface. QXRD analysis of saprolite, argillic, and soil A-horizons in the profiles highlights the imprint of bedrock on the regolith, which includes Neoproterozoic meta-tonalitic to meta-granodioritic and Paleozoic meta-granitic to biotite- and amphibolite-gneissic lithologies. Also, aeolian input slightly influenced A-horizon composition. The clay mineral assemblage is dominated by kaolinite, but profiles differ in the amount of interstratified clay minerals, halloysite, hematite, goethite, and gibbsite. Rare-earth element totals vary between 30 and 1048 ppm and are generally correlated positively with clay and clay mineral content. Eu and Ce anomalies reflect parent rocks and subsequent hydrolysis and redox history, with trends depending upon landscape position and clay content in the weathering profile. Weathering profiles on a high-order interfluve and those that were actively cultivated have thick argillic horizons (as defined by clay mineral abundance) and are depleted in alkali and alkaline-earth elements. Profiles proximally developed on old-field pine and never-cultivated hardwood forest land do not show large differences in mineral composition trends, whereas profiles on old-field sites with ongoing cultivation exhibit assemblages enriched in clay minerals and (oxyhydr)oxides. Old-field pine sites that were historically eroded by previous cultivation tend to have shallower and thinner argillic horizons, which may well impact critical-zone processes involving gas and water fluxes. This study highlights that mineral compositions of deep regolith, saprolite, and shallow soil horizons are dependent on local geomorphology (i.e. watershed- and hillshed-orders). Quantifying soil and regolith compositional trends across the landscape is a prerequisite for determining rates of chemical and physical erosion on human and geologic time scales.

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Lithological control on the formation of ferruginous duricrusts in the Espinhaço Range (Minas Gerais, Brazil)

Milagres

Oliveira

Varajão

et al. 2023

CATENA

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Rare earth elements in gneiss regoliths in southern Minas Gerais, Brazil

Cited by 3 publications

References 43 publications

Occurrence of some rare earth elements in vineyard soils under semiarid Mediterranean environment

Occurrence of some rare earth elements in vineyard soils under semiarid Mediterranean environment

Mineralogical and Elemental Trends in Regolith on Historically Managed Sites in the southeastern United States Piedmont

Lithological control on the formation of ferruginous duricrusts in the Espinhaço Range (Minas Gerais, Brazil)

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