Iron isotopic fractionation during continental weathering

Fantle, Matthew S.; DePaolo, Donald J.

doi:10.1016/j.epsl.2004.10.013

Cited by 194 publications

(142 citation statements)

References 74 publications

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…[14,15,22] Ammonium acetate extracts of two of the desert soils gave an average δ 56 Fe value of −0.06‰, which suggests that the labile iron fraction (as defined by our procedures) in desert soils is isotopically similar to the total iron fraction.…”

mentioning

confidence: 97%

Global dust teleconnections: aerosol iron solubility and stable isotope composition

et al. 2007

View full text Add to dashboard Cite

Environmental context. Iron is an essential component of many enzyme systems of marine plants (phytoplankton), but in large areas of the global ocean iron is in such short supply as to hinder phytoplankton growth. This is of major environmental interest because phytoplankton growth can remove carbon from the atmosphere. This contribution seeks to improve the understanding of how dust transported through, and processed within, the atmosphere helps to supply usable iron to the plants of the remote ocean.Abstract. Soil dust mobilised from arid regions is transported through and processed within the atmosphere before deposition to marine and terrestrial ecosystems remote from the source regions. This process represents a significant source of iron to the oceans, which creates feedback loops throughout the Earth's system. The very limited solubility of iron from dust makes the determination of this solubility, how it varies and how this may influence ocean biogeochemistry of considerable importance. In this short communication we summarise a series of recent studies of mechanisms that control solubility and then consider how these results influence the inputs of iron to the oceans and their isotopic signature.

show abstract

mentioning

confidence: 97%

Global dust teleconnections: aerosol iron solubility and stable isotope composition

et al. 2007

View full text Add to dashboard Cite

show abstract

“…In addition, we distinguished between amorphous and crystalline iron-oxy-hydroxide phases (Wiederhold et al, 2007). Accordingly, our extraction method, for which between 0.5 and 0.75 g of dried, sieved sediment were used (see Tables 1,2), involves five steps: 1) Extraction of the exchangeable "Ex" fraction by using 1M magnesiumchloride (MgCl 2 ) solution, 2) Extraction of the reactive amorphous oxy-hydroxide "Am-Ox" fraction by using 0.5M HCl (Fantle and DePaolo, 2004;Wiederhold et al, 2007). This treatment would also dissolve the CaCO 3 that is present in the sample, but most likely does not dissolve silicate minerals (Guelke et al, 2010).…”

Section: 1mentioning

confidence: 99%

The dependence of meteoric 10Be concentrations on particle size in Amazon River bed sediment and the extraction of reactive 10Be/9Be ratios

et al. 2012

View full text Add to dashboard Cite

(2012): The dependence of meteoric 10Be concentrations on particle size in Amazon River bed sediment and the extraction of reactive 10Be/9Be ratios. AbstractConcentrations of meteoric 10 Be extracted from detrital Amazon river sediment are strongly particle size-dependent. Such grain size dependency presents a formidable obstacle to routine applications of meteoric cosmogenic 10 Be to basin-wide erosion studies. In this study, we explore means to eliminate these grain size effects in bedload from rivers of the Amazon basin by measuring 10 Be/ 9 Be ratios after selective chemical extraction of reactive authigenic phases. These phases mainly comprise FeMn(hydr)oxides that are the main carriers of 9 Be and 10 Be. We explore the distribution of 10 Be and its stable 9 Be counterpart between these phases and the partitioning of Be into remaining silicate fractions.This extraction procedure was carried out on bedload samples comprising the three main tectonic units of the Amazon basin, namely the Andes, the Guyana and Brazilian Shields, and the central Amazonian lowlands. For all samples, extracted 10 Be concentrations show a strong decrease with increasing particle size, with up to 20 times more 10 Be extracted from the finest analyzed (<30 μm) grain size when compared to the coarsest (90-125 μm) grain size. We attribute this decrease in 10 Be concentrations mostly to subsequent dilution by quartz in coarse bedload. However, when normalized to stable 9 Be concentrations that are also extracted from reactive phases, grain size effects are effectively removed

show abstract

“…Stable Fe isotope analyses provide valuable information on the fate of Fe and are a promising tool for addressing questions on pedogenetic processes and soil evolution (e.g., Beard et al, 2003), particularly the identification of the mechanisms involved in a pedogenesis. While a range of isotopic variations from − 0.62 to + 0.72‰ have been documented in soils (Emmanuel et al, 2005;Fantle and DePaolo, 2004;Poitrasson et al, 2008;Thompson et al, 2007;Wiederhold et al, 2007aWiederhold et al, , 2007bFekiacova et al, 2013) no clear link between isotopic variations and pedogenetic mechanisms has yet been established. Iron isotopic fractionation related to pedogenesis is complex and is a function of the soil type.…”

Section: Introductionmentioning

confidence: 99%

Can Fe isotope fractionations trace the pedogenetic mechanisms involved in podzolization?

et al. 2017

View full text Add to dashboard Cite

a b s t r a c t a r t i c l e i n f oStable Fe isotopes have shown the potential for tracing pedogenetic processes. Large isotopic fractionations were especially observed in Podzols. Nevertheless, a clear link between isotopic fractionation and elementary processes still needs to be established. To spatially distinguish the mechanisms successively involved in pedogenesis, we studied a podzolic chronosequence from Vancouver Island (British Columbia, Canada). We analyzed depth variations in soil properties (pH, particle size fractions, organic carbon, Si/Al ratio, Zr, Ti), Fe concentrations in different Fe pools, and Fe isotopic compositions. The Si/Al ratio, Zr, and Ti demonstrated that the Cox Bay Podzols developed from the same parental material, satisfying the requirements of a chronosequence. We showed that acidification, to a pH of 4.7, was a prerequisite for the start of podzolization. This first phase took place after 270 years. Furthermore, we observed that once the required pH was reached (4.7), podzolization occurred rapidly over 50 years. We found that Fe isotope fractionation in the A/E horizon was linked to mineral dissolution, while in the podzolic B horizons this fractionation was clearly associated with the accumulation of Fe-organic complexes and poorly crystalline Fe oxyhydroxides.

show abstract

Iron isotopic fractionation during continental weathering

Cited by 194 publications

References 74 publications

Global dust teleconnections: aerosol iron solubility and stable isotope composition

Global dust teleconnections: aerosol iron solubility and stable isotope composition

The dependence of meteoric 10Be concentrations on particle size in Amazon River bed sediment and the extraction of reactive 10Be/9Be ratios

Can Fe isotope fractionations trace the pedogenetic mechanisms involved in podzolization?

Contact Info

Product

Resources

About