Mobility and fractionation of rare earth elements during supergene weathering and gossan formation and chemical modification of massive sulfide gossan

Leybourne, Matthew I.; Peter, Jan M.; Layton‐Matthews, Daniel; Volesky, John C.; Boyle, Dan R.

doi:10.1016/j.gca.2005.11.003

Cited by 44 publications

(29 citation statements)

References 68 publications

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“…Surface and groundwater samples from the Pettaquamscutt Estuary have negative Eu anomalies ( Table 3) that most likely reflect waterrock interactions with the local bedrock and glacial deposits, all of which are also characterized by negative Eu anomalies (e.g., Buma et al, 1971;Taylor and McLennan, 1985;Maria and Hermes, 2001;Dorias, 2003;Schulz et al, 2008;Dorias et al, 2012). Furthermore, it is unlikely that redox conditions are sufficiently reducing in the Pettaquamscutt subterranean estuary to reduce Eu 3+ to Eu 2+ (Sverjensky, 1984;Middelburg et al, 1988;Leybourne et al, 2006;Leybourne and Johannesson, 2008). In addition, geochemical modeling of E h using the SpecE8 and Act1 program of Geochemist's Workbench® (release 7.0; Bethke, 2008) further suggests that the redox conditions are not sufficiently reducing to form Eu 2+ .…”

Section: Ree Concentrationsmentioning

confidence: 99%

Submarine groundwater discharge of rare earth elements to a tidally-mixed estuary in Southern Rhode Island

et al. 2015

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a b s t r a c tRare earth element (REE) concentrations were analyzed in surface water and submarine groundwater within the Pettaquamscutt Estuary, located on the western edge of Narragansett Bay in Rhode Island. These water samples were collected along the salinity gradient of the estuary. Rare earth element concentrations in the majority of the groundwater samples are substantially higher than their concentrations in the surface waters. In particular, Nd concentrations in groundwater range from 0.43 nmol kg −1 up to 198 nmol kg −1 (mean ± SD = 42.1 ± 87.2 nmol kg −1 ), whereas Nd concentrations range between 259 pmol kg −1 and 649 pmol kg −1 (mean ± SD = 421 ± 149 pmol kg −1 ) in surface waters from the estuary, which is, on average, 100 fold lower than Nd in the groundwaters. Groundwater samples all exhibit broadly similar middle REE (MREE) enriched shalenormalized REE patterns, despite the wide variation in pH of these natural waters (4.87 ≤ pH ≤ 8.13). The similarity of the shale-normalized REE patterns across the observed pH range suggests that weathering of accessory minerals, such as apatite, and/or precipitation of LREE enriched secondary phosphate minerals controls groundwater REE concentrations and fractionation patterns. More specifically, geochemical mixing models suggest that the REE fractionation patterns of the surface waters may be controlled by REE phosphate mineral precipitation during the mixing of groundwater and stream water with incoming water from the Rhode Island Sound. The estimated SGD (Submarine Groundwater Discharge) of Nd to the Pettaquamscutt Estuary is 26 ± 11 mmol Nd day −1 , which is in reasonable agreement with the Nd flux of the primary surface water source to the estuary, the Gilbert Stuart Stream (i.e., 36 mmol day −1 ), and of the same order of magnitude for a site in Florida.

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Section: Ree Concentrationsmentioning

confidence: 99%

Submarine groundwater discharge of rare earth elements to a tidally-mixed estuary in Southern Rhode Island

et al. 2015

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“…This lanthanide contraction imparts subtle and systematic differences in the chemical properties of REEs across the series that are largely predictable, and thus highly useful in studies of those processes that fractionate REEs in the environment. Consequently, the REEs have a long history of use in the study of magma genesis in the Earth's upper mantle and crust, crustal evolution, and in investigating weathering, crustal denudation, transport of weathering products to the oceans, and for water-rock interactions (Hanson, 1980;Henderson, 1984;Taylor and Mclennan, 1985;Banfield and Eggleton, 1987;Banner et al, 1989;Braun et al, 1990;Bau, 1991;Smedley, 1991;Leybourne et al, 2006b).…”

Section: Introductionmentioning

confidence: 99%

Rare earth elements (REE) and yttrium in stream waters, stream sediments, and Fe–Mn oxyhydroxides: Fractionation, speciation, and controls over REE+Y patterns in the surface environment

Leybourne

Johannesson

2008

Geochimica et Cosmochimica Acta

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258

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“…The variation of the Pb concentration will influence the equilibrium between plumbojarosite and anglesite. There is field evidence of replacement of plumbojarosite by anglesite (Leybourne et al, 2006) and dissolution of anglesite and precipitation of plumbojarosite (Ostergren et al, 1999 that Pb speciation, and phases formed are closely balanced and strongly influenced by the environmental conditions. These findings also enable an estimate of the solubility product K sp (plumbojar) of pure plumbojarosite by considering the dissolution reaction: …”

Section: Calorimetrymentioning

confidence: 99%

Synthesis, characterization and thermochemistry of a Pb-jarosite

Forray

Smith

Drouet

et al. 2010

Geochimica et Cosmochimica Acta

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The enthalpy of formation from the elements of a well-characterized synthetic Pb-jarosite sample corresponding to the chemical formula (H 3 O) 0.74 Pb 0.13 Fe 2.92 (SO 4 ) 2 (OH) 5.76 (H 2 O) 0.24 was measured by high temperature oxide melt solution calorimetry. This value (DH f = À3695.9 ± 9.7 kJ/mol) is the first direct measurement of the heat of formation for a lead-containing jarosite. Comparison to the thermochemical properties of hydronium jarosite and plumbojarosite end-members strongly suggests the existence of a negative enthalpy of mixing possibly related to the nonrandom distribution of Pb 2+ ions within the jarosite structure. Based on these considerations, the following thermodynamic data are proposed as the recommended values for the enthalpy of formation from the elements of the ideal stoichiometric plumbojarosite Pb 0.5 Fe 3 (SO 4 ) 2 (OH) 6 : DG f = À3118.1 ± 4.6 kJ/mol, DH f = À3603.6 ± 4.6 kJ/mol and S°= 376.6 ± 4.5 J/(mol K). These data should prove helpful for the calculation of phase diagrams of the Pb-Fe-SO 4 -H 2 O system and for estimating the solubility product of pure plumbojarosite. For illustration, the evolution of the estimated solubility product of ideal plumbojarosite as a function of temperature in the range 5-45°C was computed (Log(K sp ) ranging from À24.3 to À26.2). An Eh-pH diagram is also presented.

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Mobility and fractionation of rare earth elements during supergene weathering and gossan formation and chemical modification of massive sulfide gossan

Cited by 44 publications

References 68 publications

Submarine groundwater discharge of rare earth elements to a tidally-mixed estuary in Southern Rhode Island

Submarine groundwater discharge of rare earth elements to a tidally-mixed estuary in Southern Rhode Island

Rare earth elements (REE) and yttrium in stream waters, stream sediments, and Fe–Mn oxyhydroxides: Fractionation, speciation, and controls over REE+Y patterns in the surface environment

Synthesis, characterization and thermochemistry of a Pb-jarosite

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