Rare Earth Elements abundance, fractionation, and anomalies in the sediments of the Cananéia-Iguape Estuarine-Lagoon Complex in Brazil

Chiozzini, Vitor G.; Fávaro, Deborah I. T.; Braga, Elisabete S.

doi:10.1590/2675-2824071.22087vgc

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Ocean and Coastal Research

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Original Article • Ocean Coast. Res. 71 (suppl 1) • 2023 • https://doi.org/10.1590/2675-2824071.22087vgc copy

Rare Earth Elements abundance, fractionation, and anomalies in the sediments of the Cananéia-Iguape Estuarine-Lagoon Complex in Brazil

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

The Cananéia-Iguape Estuarine-Lagoon Complex (CIELC) is an extremely productive coastal ecosystem. It encloses the Valo Grande channel, built 160 years ago, which introduces water from the Ribeira River directly into the estuarine system, contributing to important biogeochemical changes in the region. Many nutrients arrive at the estuary through this channel, as well as metals and other slightly soluble elements that become part of the sediments. This study aims to evaluate the processes that govern the distribution of rare earth elements (REE) in the sediments of the complex by using fractionation patterns, anomalies, and the geochemical signature of minerals to evaluate sources, natural levels, and the possible anthropogenic forcing to which CIELC is subjected. ∑REE* ranged from 14.2 to 285 mg kg ^-1 and showed a distribution related to depositional/textural characteristics influenced by the regional and local lithological setting and a possible contamination. The REE/Al ratio indicated enrichment in the sea adjacent to the estuary and at stations in the Ribeira River and Valo Grande. While the Hf/Al ratio indicated natural enrichment related to the presence of heavy minerals in most of these stations, this ratio fails to justify enrichment at some stations in the northern part of the estuary and the Ribeira River. Fractionation patterns and anomalies allowed us to identify the main heavy minerals related to REE enrichment at CIELC. Cerium (Ce) anomalies showed a possible relation with biologically mediated Ce ⁺³ to Ce ⁺⁴ oxidation processes in the most productive areas of the estuary. Europium (Eu) anomalies were strongly associated with different mineral assemblies in several CIELC sectors. Abundance, fractionation patterns, and REE anomalies corroborate the categorization of CIELC sediments as part of a pristine system in its southern region and as subject to anthropogenic influences in its northern area.

Descriptors:
REE Geochemistry; Estuarine RAMSAR Area; Trace Metals; Biogeochemistry; Phosphogypsum

Heavy mineral	Average content in the region (%) ^a a relative content of each heavy mineral considering the total assembly of heavy minerals. Values calculated from Tessler ( 1988);	ΣREE content ^b b composition in ΣETR and other major elements in the minerals obtained from “Mineralogy Data Base” (www.mindat.org), Yang et al. ( 2002) for apatite, Jang and Naslund (2003) and Karimpour et al. (2009) for ilmenite, and complemented with observations by Clark (1984).	Main elements in the composition ^b b composition in ΣETR and other major elements in the minerals obtained from “Mineralogy Data Base” (www.mindat.org), Yang et al. ( 2002) for apatite, Jang and Naslund (2003) and Karimpour et al. (2009) for ilmenite, and complemented with observations by Clark (1984).	Main REE characteristics ^b b composition in ΣETR and other major elements in the minerals obtained from “Mineralogy Data Base” (www.mindat.org), Yang et al. ( 2002) for apatite, Jang and Naslund (2003) and Karimpour et al. (2009) for ilmenite, and complemented with observations by Clark (1984).
Alanite	-	~18%	Ca, Al, Fe, Si, Hf	LREE enrichment, mainly La and Ce
Apatite	-	1 to 12%	Ca 40%, P 18%	LREE enrichment, negative Eu anomaly, positive Ce anomaly
Augite	< 0.5%	~ 1%	Ca, Mg, Fe, Si, Al	HREE enrichment, positive Eu anomaly
Garnet	~ 3.0%	0.5 to 4%	Mg, Ca, Fe, Al, Cr, Hf	HREE Enrichment, negative Eu anomaly, positive Ce anomaly
Hyperstene	< 2%	~ 2%	Mg 10%, Fe 25%, Si 25%	HREE Enrichment, positive Eu anomaly
Hornblende	~ 15%	-	Si, Al, Ca, Fe, Mg	MREE enrichment followed by LREE enrichment
Ilmenite	~ 1.5%	10 to 200 mg kg ^-1	Fe 37%, Ti 32%	Equally enriched in all REE
Monazite	< 0.5 %	~ 56%	Th 5%, P 13%	LREE enrichment (especially La), negative Eu anomaly
Titanite	< 0.5 %	~ 4%	Ti 18%, Ca 19%	LREE enrichment
Zirconite	~ 22%	~ 4%	Th, Zr 43%, Hf 5%, Si 15%	HREE enrichment, negative Eu anomaly

Studied region	Ʃ REE		[La/Yb] _UCC		[Ce/Ce ^* * in this study, ∑REE = ∑REE*; ] _UCC		[Eu/Eu ^* * in this study, ∑REE = ∑REE*; ] _UCC		Quantification method	References
Studied region	Min	Max	Min	Max	Min	Max	Min	Max	Quantification method	References
CIELC, Brazil	14.3	285.0	0.80	1.67	0.63	1.06	0.56	1.56	INAA	This study ^* * in this study, ∑REE = ∑REE*;
Santos-S. Vicente (Brazil)	194	254	1.43	2.47	1.09	1.21	0.54	0.82	INAA	( Oliveira et al., 2007Oliveira, S., Silva, P., Mazzilli, B., Favaro, D. & Saueia, C. 2007. Rare earth elements as tracers of sediment contamination by phosphogypsum in the Santos estuary, southern Brazil. Applied Geochemistry, 22(4), 837–850. DOI: https://doi.org/10.1016/j.apgeochem.2006.12.017 https://doi.org/10.1016/j.apgeochem.2006... ) ^ in Oliveira et al. ( 2007), ∑REE = (La+Ce+Nd+Sm+Eu+Tb+Yb+Lu); (no phosphogypsum contamination)
Marabasco estuary, Mexico	27.5	157.0	0.49	1.64	0.88	0.94	0.81	2.22	INAA	( Marmolejo-Rodríguez et al., 2007Marmolejo-Rodríguez, A., Prego, R., Meyer-Willerer, A., Shumilin, E. & Sapozhnikov, D. 2007. Rare earth elements in iron oxy−hydroxide rich sediments from the Marabasco River-Estuary System (pacific coast of Mexico). REE affinity with iron and aluminium. Journal of Geochemical Exploration, 94(1–3), 43–51. DOI: https://doi.org/10.1016/j.gexplo.2007.05.003 https://doi.org/10.1016/j.gexplo.2007.05... )
Vigo ria – Pontevedra, Spain	2.0	220.0	0.65	2.29	0.71	1.00	0.79	1.41	ICP-MS	( Prego et al., 2009Prego, R., Caetano, M., Vale, C. & Marmolejo-Rodríguez, J. 2009. Rare earth elements in sediments of the Vigo Ria, NW Iberian Peninsula. Continental Shelf Research, 29(7), 896–902. DOI: https://doi.org/10.1016/j.csr.2009.01.009 https://doi.org/10.1016/j.csr.2009.01.00... )
Mandovi estuary, western India	37.1	160.4	0.49	0.91	0.77	1.77	1.27	1.76	ICP-MS	( Prajith et al., 2015Prajith, A., Rao, V. & Kessarkar, P. 2015. Controls on the distribution and fractionation of yttrium and rare earth elements in core sediments from the Mandovi estuary, western India. Continental Shelf Research, 92, 59–71. DOI: https://doi.org/10.1016/j.csr.2014.11.003 https://doi.org/10.1016/j.csr.2014.11.00... )
Bohai Bay, China	97.6	202.0	0.86	1.00	0.89	1.03	1.14	1.51	ICP-MS	Zhang et al., 2014
Huelva Ria, Spain	36.0	197.7	0.80	3.26	0.80	1.43	0.93	1.18	ICP-MS	( Borrego et al., 2004Borrego, J., López-González, N., Carro, B. & Lozano-Soria, O. 2004. Origin of the anomalies in light and middle REE in sediments of an estuary affected by phosphogypsum wastes (south-western Spain). Marine Pollution Bulletin, 49(11–12), 1045–1053. DOI: https://doi.org/10.1016/j.marpolbul.2004.07.009 https://doi.org/10.1016/j.marpolbul.2004... ) (no phosphogypsum contamination)
Johore straight, Malaysia	36.0	162.0	0.99	1.75	0.44	2.04	-	-	INAA	( Yusof et al., 2001Yusoff, Z., Ngwenya, B. & Parsons, I. 2013. Mobility and fractionation of REEs during deep weathering of geochemically contrasting granites in a tropical setting, Malaysia. Chemical Geology, 349–350, 71–86. DOI: https://doi.org/10.1016/j.chemgeo.2013.04.016 https://doi.org/10.1016/j.chemgeo.2013.0... ) ^* ***** in Yusof et al. ( 2001), ∑REE = (La+Ce+Sm+Eu+Tb+Dy+Y).

Instituto Oceanográfico da Universidade de São Paulo Praça do Oceanográfico 191, CEP: 05508-120, São Paulo, SP - Brasil, Tel.: (11) 3091-6501 - São Paulo - SP - Brazil
E-mail: diretoria.io@usp.br

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[1] * Corresponding author: vitor.chio@usp.br