Modeling of rare-earth element partitioning between particles and solution in aquatic environments

Journal Article · Mon Feb 01 04:00:00 EST 1993 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(93)90363-2· OSTI ID:6706085

Erel, Y; Stolper, E M ^[1]

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1. California Inst. of Technology, Pasadena (United States)

The authors have modeled the partitioning of rare earth elements (REEs) between O-donor surface groups and aqueous solutions with a simple thermodynamic treatment. Their model predicts that the La-normalized ratios of adsorbed to dissolved REEs depend primarily on the first hydroxide binding contants of the REEs, their first and second carbonate complexing constants, and the ionic strength and carbonate concentration of the solution. For modern and for ancient seawater, they predict an overall light REE (LREE) enrichment of surfaces relative to coexisting aqueous solutions and a positive Eu anomaly in the adsorbed component. The REE pattern of average modern ocean water can be explained quantitatively if the oceans are equilibrated with particle surfaces having REE patterns similar to average upper continental crust. Applying their treatment to the REE patterns of sediments from the Archean Hamersley-basin iron formation, they show that the observed positive Eu anomalies and LREE depletions of these rocks can be qualitatively accounted for if a significant fraction of the REEs in these rocks were initially present as an adsorbed component equilibrated with Archean ocean water that had no Eu anomaly. This suggests that the sources of REEs in the Archean ocean could have been dominantly continental as they are today and that the observed positive Eu anomalies of banded iron formations need not be inherited from the aqueous solutions from which they were deposited and do not necessarily indicate a significant ocean hydrothermal component in these solutions. 42 refs., 3 figs.

• OSTI ID: 6706085
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 57:3; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AQUEOUS SOLUTIONS
BINDING ENERGY
CARBON COMPOUNDS
CARBONATES
CONTINENTAL CRUST
DISPERSIONS
DISTRIBUTION
EARTH CRUST
ECOLOGICAL CONCENTRATION
ELEMENTS
ENERGY
ENRICHMENT
EQUILIBRIUM
HYDROGEN COMPOUNDS
HYDROXIDES
IRON
METALS
MIXTURES
OXYGEN COMPOUNDS
PARTICLES
PARTITION
RARE EARTHS
ROCKS
SEAWATER
SEDIMENTS
SOLUTIONS
SPATIAL DISTRIBUTION
SURFACES
TRANSITION ELEMENTS
WATER