Distribution of the rare earth elements in sediments of the Northwestern Iberian Continental Shelf

Araújo, M. Fátima; Corredeira, Catarina; Gouveia, A.

doi:10.1007/s10967-007-0201-6

Cited by 17 publications

(8 citation statements)

References 6 publications

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“…In the Northern Galician shelf REE pattern is more discernible than in the Loire and Gironde estuarine sediments where REE did not permit to discriminate between the possible continental sources (Joaunneau et al, 1998). The sediments of northern Galician coast also show a deficit of REE compared with sediments of the west coast of the Iberian Peninsula at Douro and Galicia mud patches (Joaunneau et al, 2002;Araújo et al, 2007) and at east coast of the Cantabrian Sea at the American and Aquitania shelves (Joauneau et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

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Rare earth elements in coastal sediments of the northern Galician shelf: Influence of geological features

Prego¹,

Caetano

Bernárdez³

et al. 2012

Continental Shelf Research

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The Northern coast of Galicia, NW Iberian Peninsula, exhibits a variety of geological features: Ortegal allochthonous complex, Ollo-de-Sapo autochthonous domain and massifs of Bares, Barqueiro and San-Ciprian. In order to examine the influence of terrestrial lithologies on coastal sediments, 103 samples were collected in the Rias of Ortigueira, Barqueiro and Viveiro, their neighbouring shelf and the estuaries of Mera, Sor and Landro rivers. Aluminium, Fe, Sc, particulate inorganic and organic carbon and rare earth elements (REE) were determined in the <2 mm fraction. In addition, calcite, muscovite, quartz and riebeckite minerals were identified and quantified in 33 selected samples. The distributions of riebeckite and Fe reflect the influence of Ortegal complex on the coastal areas around the Cape Ortegal. The highest concentrations of ΣREE were found in fine sediments from confined inner parts of the Rias (up to 233 mg•kg-1), while most of the sands contained 11-70 mg•kg-1. ΣREE normalized to European Shale (ES) highlights the relative abundance of lanthanides (ΣREE N >6) near Cape Ortegal and the innermost ria zones. The ratio between light and heavy REE (L/H) showed lower values (4-11) around Cape Ortegal and the shelf while higher ratios (15-23) were detected in west of the Cape Estaca-de-Bares and in the inner Viveiro Ria due to elevated contributions of La and Ce. The L/H values normalized to ES reflects the importance of HREE in the adjacent area to Ortegal Complex (L N /H N <0.8) and the LREE (L N /H N >1.4) in the inner estuaries and west Cape Estaca-de-Bares. The highest REE individual ES normalised were measured in fine-grained sediments of the Mera and Sor estuaries. Sediments from the eastern shelf of Cape Ortegal presented enhanced ratios only for HREE. These results indicate that distribution of REE in the northern Galician region is highly depending on the neighbouring lithological pattern, contrasting with the situation found in the western Galician shelf and the Bay of Biscay. Lanthanides can, thus, provide a useful tool to follow the sediment pathway in the land-sea boundary zones, denoting continental geochemical imprint or fluvial outputs accordingly to the existing hydrological and geological conditions.

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Section: Discussionmentioning

confidence: 99%

“…Total REE (ΣREE) and European Shale normalization average (or the range in its absence) for different surface sediment zones of Galician Rias and Shelf. Araújo et al, 2007…”

mentioning

confidence: 99%

Rare earth elements in coastal sediments of the northern Galician shelf: Influence of geological features

Prego¹,

Caetano

Bernárdez³

et al. 2012

Continental Shelf Research

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“…It is often responsible for hosting the REE due to its larger cation sites that can easily accept many of the REE ions, which then may become a minor component of the mineral (Jones et al 1996). Under natural conditions, Zr and Hf well present a positive correlation with both LREE and HREE (Araú jo et al 2007). In Araú jo's (2007) study, the correlation coefficients of Zr with La, Ce, Sm, Tb, Yb, and Lu are 0.78, 0.80, 0.80, 0.72, 0.85, and 0.86 on the Northern Iberian shelf along the area between the Finisteria Cape and the mouth of the Minho River, which is an almost pure area.…”

Section: Sediments Pollution In Tolo Harbourmentioning

confidence: 93%

“…Chen et al (2010) also documented that the area where sites Y and Z are located has very high Ca concentration, accumulated shells and intense biological activity. Therefore, the significantly lower concentrations of P REE, P LREE and P HREE at sites Y and Z (Table 2) relative to other sites should be related to the enrichment of calcareous biological debris, which dilute the REE abundances in the sediments (Araú jo et al 2007;Caccia et al 2007;Taylor and McLennan 1985).…”

Section: Ree Anomalies Of Samples At Sites Y and Zmentioning

confidence: 99%

Rare Earth Elements Geochemistry and Provenance Discrimination of Sediments in Tolo Harbour, Hong Kong

Chen

Yang

Jiao

2014

Marine Georesources & Geotechnology

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Rare earth elements (REE) concentrations have been analyzed in 13 sediment samples from Tolo Harbour. The highest concentrations of P REE, P LREE (light rare earth elements) and P HREE (heavy rare earth elements) are all at site G as the enrichment of Mn-Fe oxyhydroxides and the highest pH of site G relative to its nearby areas. The relatively higher P LREE= P HREE ratio at site G is probably due to the stronger REE fractionation. During the fractionation process, LREE are preferentially scavenged on particle surfaces such as Mn-Fe oxyhydroxides and clay minerals. Concentrations of P REE, P LREE and P HREE at sites Y and Z are much lower than those at other sites as calcareous biological debris dilute the REE abundances of the sediments in Tolo Harbour. REE are released from sediments into waters due to the high salinity in Tolo Harbour and REE fractionation occurs in this release process. The provenance of sediments in Tolo Harbour is terrigenous and the North American shale composite (NASC)-normalized REE patterns of the 13 samples in Tolo Harbour all display strongly negative Eu anomalies. P REE is poorly correlated with Zr and Hf, which suggests that Tolo Harbour is heavily polluted by human activities.

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“…Monazite frequently has relatively high thorium contents (Licht, 2001). Zirconium and Hf can be associated with heavy minerals (such as titanite, apatite, zircon, epidote, garnet and clay minerals) which may also control the REE distribution (Araújo et al, 2007). Thus, positive correlations of Ce, La, Y and Sc with Zr, Hf and Th should indicate a common source of these chemical elements, that is, the one with Variscan granitic and gneissic rocks.…”

Section: Possible Sources Of the Sediments In The Study Areamentioning

confidence: 99%

Geochemical Normalizers Applied to the Study of the Provenance of Lithogenic Materials Deposited at the Entrance of a Coastal Lagoon. A Case Study in Aveiro Lagoon (Portugal) / Normalizadores Geoquímicos Aplicados Ao Estudo De Proveniência De Materiais Litogénicos Depositados Na Entrada De Uma Laguna Costeira. Um Estudo De Caso Na Laguna De Aveiro (Portugal)

et al. 2018

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The use of geochemical normalizers has been applied in sedimentological studies in several study contexts, such as pollution, diagenetic and provenance assessment. Selected textural and mineralogical data of 137 surface sediment samples were compared by statistical analyses with geogenic elements concentrations normalized by the Al, Be, Ce, Fe, Fe+Al, Li, Rb and Sc aiming to identify the best normalizer to trace different sources of bottom sediments for the Aveiro Lagoon entrance (NW of Portugal). The study area is heterogenous in terms of hydrodynamics and sedimentary processes.The most commonly applied geochemical normalizer for the sediments elemental concentrations has been the aluminum. However, the statistical analyses evidenced that the best normalizer was the scandium, since Principal Components Analysis results have evidenced that the element/Sc values are largely independent of sediment granulometry and thus have allowed the identification of compositional differences not related to grain size. Statistical analyses have also allowed to discriminate groups of stations that: i) trace the entry and exit of mixed sources sediments of the lagoon due to the action of tidal currents; ii) contain materials provided from the erosion of granitoids present mainly along the Douro River basin, located to the north, and transported southward by coastal drift; iii) encompasse sediments provided from the erosion of the Schist–Greywacke Complex crossed by the Vouga River that drains into the inner central zone of the lagoon and; iv) represent an area of sediment accumulation located near the entrance of Mira Channel, where lithogenic materials, provided by mixed lithologies in addition to organic matter, are being deposited. The results of this work contribute to the knowledge of the sedimentary dynamics of the Aveiro Lagoon, a coastal system which is part of a littoral stretch that is being strongly eroded, due to natural and anthropic causes and should be applicable to other coastal systems with similar characteristics. ResumoO uso de normalizadores geoquímicos tem sido aplicado em estudos sedimentológicos em diversos contextos, como por exemplo, de poluição, avaliação diagenética e de proveniência de sediments. Dados texturais e mineralógicos selecionados de 137 amostras de sedimentos superficiais foram comparados através de análises estatísticas com concentrações de elementos geogênicos normalizadas por Al, Be, Ce, Fe, Fe + Al, Li, Rb e Sc. O estudo visou identificar o melhor normalizador para traçar diferentes fontes de sedimentos de fundo para a entrada da Lagoa de Aveiro (NW de Portugal), uma área heterogênea em termos de processos hidrodinâmicos e sedimentares.O normalizador geoquímico mais comumente aplicado em sedimentos tem sido o alumínio. No entanto, as análises estatísticas evidenciaram que o melhor normalizador foi o escândio, uma vez que os resultados da análise de componentes principal evidenciaram que os valores das razões elemento/Sc são amplamente independentes da granulometria sedimentar e permitiram a identificação de diferenças composicionais não relacionadas com o tamanho do grão. Análises estatísticas também permitiram discriminar grupos de estações que: i) traçam a entrada e saída de fontes mistas de sedimentos da laguna, devido à ação das correntes de maré; ii) contêm materiais provenientes da erosão de granitóides presentes principalmente ao longo da bacia do Rio Douro, localizada a norte, e transportados para sul por deriva litoral; iii) contêm sedimentos provenientes da erosão do Complexo Xisto-grauvaquico atravessado pelo Rio Vouga, que desagua na zona central interna da laguna e; iv) representam uma área de acumulação de sedimentos localizada perto da entrada do Canal Mira, onde materiais litogênicos, fornecidos por litologias diversificadas, além de matéria orgânica, estão sendo depositados.Os resultados deste trabalho contribuem para o conhecimento da dinâmica sedimentar da Laguna de Aveiro, um sistema costeiro que faz parte de um trecho litorâneo fortemente erodido, devido a causas naturais e antrópicas and may be applicable to other coastal systems with similar characteristics.

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Distribution of the rare earth elements in sediments of the Northwestern Iberian Continental Shelf

Cited by 17 publications

References 6 publications

Rare earth elements in coastal sediments of the northern Galician shelf: Influence of geological features

Rare earth elements in coastal sediments of the northern Galician shelf: Influence of geological features

Rare Earth Elements Geochemistry and Provenance Discrimination of Sediments in Tolo Harbour, Hong Kong

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