Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes

Angélica Vázquez-Ortega, David Huckle, Julia Perdrial, Mary Kay Amistadi, Matej Durcik, Craig Rasmussen, Jennifer McIntosh, Jon Chorover

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Prior studies indicate that patterns of rare earth element (REE) depletion or enrichment in critical zone (CZ) weathering systems are sensitive to variation not only in lithology, but also in climatic and/or biological processes. Organic ligands and secondary mineral surfaces vary in complex stability with different lanthanide series metals, which can result in solid-solution fractionation during incongruent mineral dissolution. REE fractionation during precipitation of solid phase weathering products is also expected to vary with host phase affinity and aqueous geochemistry along fluid flow paths. We postulated that patterns of REE fractionation during pedogenic weathering would exhibit mass-dependent trends as a function of depth in the soil profile. We further hypothesized that REE signatures would be influenced by depth-dependent variation in water and dissolved organic carbon (DOC) fluxes resulting from topographic position of the pedon under investigation. Field-based hypothesis testing utilized instrumented pedons derived from rhyolitic bedrock overlain by mixed conifer forest in the Jemez River Basin Critical Zone Observatory (JRB-CZO). REE depletion trends correlated with topographically-induced variation in soil pore water and DOC through-fluxes occurring predominantly during winter snowmelt. Bulk regolith analyses indicated that light rare earth elements (LREE) were depleted preferentially relative to medium and heavy REE (MREE and HREE). Lateral fluxes of water and DOC through subsurface horizons in the concave hillslope pedon correlated not only with greater REE depletion, but also with greater fractionation of REE into organo-metal colloid forms (2-23%) relative to a planar site hillslope pedon (3-13%) where vertical water and DOC fluxes were predominant. MREEs were preferentially retained in secondary colloids, indicating a mechanism for their stabilization in the weathering profile. Positive Ce-anomalies in the soils were the result of Ce retention in pedogenic Fe-(oxy)hydroxides.

Original languageEnglish (US)
Pages (from-to)1-18
Number of pages18
JournalChemical Geology
Volume426
DOIs
StatePublished - May 15 2016

Fingerprint

pedon
Rare earth elements
hillslope
rare earth element
Fluxes
Weathering
Fractionation
Organic carbon
dissolved organic carbon
fractionation
Water
Colloids
weathering
Soils
carbon flux
colloid
Minerals
Metals
Hydroxides
Lanthanoid Series Elements

Keywords

  • Biological weathering
  • Critical zone
  • Mineral transformation
  • Pedogenesis
  • Rare earth elements

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geology

Cite this

Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes. / Vázquez-Ortega, Angélica; Huckle, David; Perdrial, Julia; Amistadi, Mary Kay; Durcik, Matej; Rasmussen, Craig; McIntosh, Jennifer; Chorover, Jon.

In: Chemical Geology, Vol. 426, 15.05.2016, p. 1-18.

Research output: Contribution to journalArticle

Vázquez-Ortega, Angélica ; Huckle, David ; Perdrial, Julia ; Amistadi, Mary Kay ; Durcik, Matej ; Rasmussen, Craig ; McIntosh, Jennifer ; Chorover, Jon. / Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes. In: Chemical Geology. 2016 ; Vol. 426. pp. 1-18.
@article{2a17cbd7a1b140dcb48779bd355135f2,
title = "Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes",
abstract = "Prior studies indicate that patterns of rare earth element (REE) depletion or enrichment in critical zone (CZ) weathering systems are sensitive to variation not only in lithology, but also in climatic and/or biological processes. Organic ligands and secondary mineral surfaces vary in complex stability with different lanthanide series metals, which can result in solid-solution fractionation during incongruent mineral dissolution. REE fractionation during precipitation of solid phase weathering products is also expected to vary with host phase affinity and aqueous geochemistry along fluid flow paths. We postulated that patterns of REE fractionation during pedogenic weathering would exhibit mass-dependent trends as a function of depth in the soil profile. We further hypothesized that REE signatures would be influenced by depth-dependent variation in water and dissolved organic carbon (DOC) fluxes resulting from topographic position of the pedon under investigation. Field-based hypothesis testing utilized instrumented pedons derived from rhyolitic bedrock overlain by mixed conifer forest in the Jemez River Basin Critical Zone Observatory (JRB-CZO). REE depletion trends correlated with topographically-induced variation in soil pore water and DOC through-fluxes occurring predominantly during winter snowmelt. Bulk regolith analyses indicated that light rare earth elements (LREE) were depleted preferentially relative to medium and heavy REE (MREE and HREE). Lateral fluxes of water and DOC through subsurface horizons in the concave hillslope pedon correlated not only with greater REE depletion, but also with greater fractionation of REE into organo-metal colloid forms (2-23{\%}) relative to a planar site hillslope pedon (3-13{\%}) where vertical water and DOC fluxes were predominant. MREEs were preferentially retained in secondary colloids, indicating a mechanism for their stabilization in the weathering profile. Positive Ce-anomalies in the soils were the result of Ce retention in pedogenic Fe-(oxy)hydroxides.",
keywords = "Biological weathering, Critical zone, Mineral transformation, Pedogenesis, Rare earth elements",
author = "Ang{\'e}lica V{\'a}zquez-Ortega and David Huckle and Julia Perdrial and Amistadi, {Mary Kay} and Matej Durcik and Craig Rasmussen and Jennifer McIntosh and Jon Chorover",
year = "2016",
month = "5",
day = "15",
doi = "10.1016/j.chemgeo.2016.01.001",
language = "English (US)",
volume = "426",
pages = "1--18",
journal = "Chemical Geology",
issn = "0009-2541",
publisher = "Elsevier",

}

TY - JOUR

T1 - Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes

AU - Vázquez-Ortega, Angélica

AU - Huckle, David

AU - Perdrial, Julia

AU - Amistadi, Mary Kay

AU - Durcik, Matej

AU - Rasmussen, Craig

AU - McIntosh, Jennifer

AU - Chorover, Jon

PY - 2016/5/15

Y1 - 2016/5/15

N2 - Prior studies indicate that patterns of rare earth element (REE) depletion or enrichment in critical zone (CZ) weathering systems are sensitive to variation not only in lithology, but also in climatic and/or biological processes. Organic ligands and secondary mineral surfaces vary in complex stability with different lanthanide series metals, which can result in solid-solution fractionation during incongruent mineral dissolution. REE fractionation during precipitation of solid phase weathering products is also expected to vary with host phase affinity and aqueous geochemistry along fluid flow paths. We postulated that patterns of REE fractionation during pedogenic weathering would exhibit mass-dependent trends as a function of depth in the soil profile. We further hypothesized that REE signatures would be influenced by depth-dependent variation in water and dissolved organic carbon (DOC) fluxes resulting from topographic position of the pedon under investigation. Field-based hypothesis testing utilized instrumented pedons derived from rhyolitic bedrock overlain by mixed conifer forest in the Jemez River Basin Critical Zone Observatory (JRB-CZO). REE depletion trends correlated with topographically-induced variation in soil pore water and DOC through-fluxes occurring predominantly during winter snowmelt. Bulk regolith analyses indicated that light rare earth elements (LREE) were depleted preferentially relative to medium and heavy REE (MREE and HREE). Lateral fluxes of water and DOC through subsurface horizons in the concave hillslope pedon correlated not only with greater REE depletion, but also with greater fractionation of REE into organo-metal colloid forms (2-23%) relative to a planar site hillslope pedon (3-13%) where vertical water and DOC fluxes were predominant. MREEs were preferentially retained in secondary colloids, indicating a mechanism for their stabilization in the weathering profile. Positive Ce-anomalies in the soils were the result of Ce retention in pedogenic Fe-(oxy)hydroxides.

AB - Prior studies indicate that patterns of rare earth element (REE) depletion or enrichment in critical zone (CZ) weathering systems are sensitive to variation not only in lithology, but also in climatic and/or biological processes. Organic ligands and secondary mineral surfaces vary in complex stability with different lanthanide series metals, which can result in solid-solution fractionation during incongruent mineral dissolution. REE fractionation during precipitation of solid phase weathering products is also expected to vary with host phase affinity and aqueous geochemistry along fluid flow paths. We postulated that patterns of REE fractionation during pedogenic weathering would exhibit mass-dependent trends as a function of depth in the soil profile. We further hypothesized that REE signatures would be influenced by depth-dependent variation in water and dissolved organic carbon (DOC) fluxes resulting from topographic position of the pedon under investigation. Field-based hypothesis testing utilized instrumented pedons derived from rhyolitic bedrock overlain by mixed conifer forest in the Jemez River Basin Critical Zone Observatory (JRB-CZO). REE depletion trends correlated with topographically-induced variation in soil pore water and DOC through-fluxes occurring predominantly during winter snowmelt. Bulk regolith analyses indicated that light rare earth elements (LREE) were depleted preferentially relative to medium and heavy REE (MREE and HREE). Lateral fluxes of water and DOC through subsurface horizons in the concave hillslope pedon correlated not only with greater REE depletion, but also with greater fractionation of REE into organo-metal colloid forms (2-23%) relative to a planar site hillslope pedon (3-13%) where vertical water and DOC fluxes were predominant. MREEs were preferentially retained in secondary colloids, indicating a mechanism for their stabilization in the weathering profile. Positive Ce-anomalies in the soils were the result of Ce retention in pedogenic Fe-(oxy)hydroxides.

KW - Biological weathering

KW - Critical zone

KW - Mineral transformation

KW - Pedogenesis

KW - Rare earth elements

UR - http://www.scopus.com/inward/record.url?scp=84960387619&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84960387619&partnerID=8YFLogxK

U2 - 10.1016/j.chemgeo.2016.01.001

DO - 10.1016/j.chemgeo.2016.01.001

M3 - Article

AN - SCOPUS:84960387619

VL - 426

SP - 1

EP - 18

JO - Chemical Geology

JF - Chemical Geology

SN - 0009-2541

ER -