Processes controlling the chromium isotopic composition of river water: Constraints from basaltic river catchments

D'Arcy, Joan; Babechuk, Michael G.; Døssing, Lasse Nørbye; Gaucher, Claudio; Frei, Robert

doi:10.1016/j.gca.2016.04.027

Cited by 91 publications

(52 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Considering that the average δ 53 Cr value for modern rivers is 0.5–0.6‰ above the igneous inventory, the pool of weathered Cr that is retained in soils should be lower than the igneous inventory. However, the average δ 53 Cr value for modern soils is –0.25 ± 0.23‰ (1σ; median = –0.22‰), which is close to the igneous inventory (–0.12 ± 0.10 2σ; Figure a; Berger & Frei, ; Frei & Polat, ; Paulukat et al., ; D'Arcy et al., ; Wu et al., ). This is surprising because the interpretive framework for Cr as an oxidative weathering proxy is predicated on the export of heavy Cr isotopes from the land surfaces to the oceans, which implies retention of light Cr isotopes in soils.…”

Section: Discussionsupporting

confidence: 52%

“…The Cr isotope signature of oxidative weathering can be estimated in the present day using literature data on δ 53 Cr in rivers, yielding an average value of 0.47 ± 0.39‰ (1σ; median = 0.37‰; Table S1, Supporting information) for rivers draining basaltic to granitic composition continental crust (with or without sedimentary cover; Frei & Polat, ; Paulukat, Døssing, Mondal, Voegelin, & Frei, ; Wu et al., ; D'Arcy et al., ; Figure a). This is ~0.5–0.6‰ higher than the igneous inventory (–0.12 ± 0.10‰), indicating that rivers receive isotopically fractionated Cr from soils.…”

Section: Discussionmentioning

confidence: 99%

“…One exception is the study by D'Arcy et al. () who made measurements on the clay size fraction in soils from the Connecticut River watershed, reasoning that smaller grain size fractions would contain higher proportions of weathered minerals. This approach, however, did not yield any new conclusive insights as the δ 53 Cr values reported in these clay fractions were indistinguishable from the whole‐sediment digests and the igneous inventory.…”

Section: Discussionmentioning

confidence: 99%

“…1.9 Ga. In particular, we are looking for isotopic evidence that the most weathered parts of the paleosol are enriched in light Cr isotopes relative to the igneous inventory (–0.12 ± 0.10‰, 2σ; Berger & Frei, ; D'Arcy, Babechuk, Døssing, Gaucher, & Frei, ; Wu, Wang, Reinhard, & Planavsky, ), implying that contemporaneous rivers were enriched in heavy Cr isotopes as predicted by the oxidative weathering hypothesis. The patterns of enrichment and depletion in other elements that are known to be either mobile (Na, Mg and Ca) or redox‐sensitive (Mn and Fe) during weathering are also examined.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Cr isotopic insights into ca. 1.9 Ga oxidative weathering of the continents using the Beaverlodge Lake paleosol, Northwest Territories, Canada

et al. 2019

View full text Add to dashboard Cite

The ca. 1.9 Ga Beaverlodge Lake paleosol was studied using redox‐sensitive Cr isotopes in order to determine the isotopic response to paleoweathering of a rhyodacite parent rock 500 million years after the Great Oxidation Event. Redox reactions occurring in modern weathering environments produce Cr(VI) that is enriched in heavy Cr isotopes compared to the igneous inventory. Cr(VI) species are soluble and easily leached from soils into streams and rivers, thus, leaving particle‐reactive and isotopically light Cr(III) species to build up in soils. The Beaverlodge Lake paleosol and two other published weathering profiles of similar age, the Flin Flon and Schreiber Beach paleosols, are not as isotopically light as modern soils, indicating that rivers were not as isotopically heavy at that time. Considering that the global average δ53Cr value for the oxidative weathering flux of Cr to the oceans today is just 0.27 ± 0.30‰ (1σ) based on a steady‐state analysis of the modern ocean Cr cycle, the oxidative weathering flux of Cr to the oceans at ca. 1.9 Ga would have likely been shifted to lower δ53Cr values, and possibly lower than the igneous inventory (–0.12 ± 0.10‰, 2σ). Mn oxides are the main oxidant of Cr(III) in modern soils, but there is no evidence that they formed in the studied paleosols. Cr(VI) may have formed by direct oxidation of Cr(III) using molecular oxygen or H2O2, but neither pathway is as efficient as Mn oxides for producing Cr(VI). The picture that emerges from this and other studies of Cr isotope variation in ca. 1.9 Ga paleosols is of atmospheric oxygen concentrations that are high enough to oxidize iron, but too low to oxidize Mn, resulting in low Cr(VI) inventories in Earth surface environments.

show abstract

Section: Discussionsupporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cr isotopic insights into ca. 1.9 Ga oxidative weathering of the continents using the Beaverlodge Lake paleosol, Northwest Territories, Canada

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The reduction of Cr (VI) to Cr (III) is accompanied by an isotope fractionation, resulting in an enrichment of light isotopes in the reduced Cr (III) species (e.g., Ellis et al, ), with overlapping fractionation factor ranges reported for different reductants (summarized in Wanner & Sonnenthal, ). Oxidative weathering and partial back‐reduction in riverine systems contributes isotopically heavy Cr to the ocean relative to bedrock sources (D'Arcy et al, ; Frei et al, ). Isotope fractionation associated with Cr reduction, along with the strongly different mobilities and reactivities of Cr (III) and Cr (VI), has led to the development of Cr stable isotopes (δ 53 Cr) as a useful proxy to reconstruct the oxygenation of the early earth (e.g., Frei et al, ; Frei et al, ; Planavsky et al, ) and suggests that redox cycling may control the distributions of dissolved Cr and δ 53 Cr in the modern ocean.…”

Section: Introductionmentioning

confidence: 99%

Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean

Janssen

Rickli

Quay

et al. 2020

Global Biogeochemical Cycles

View full text Add to dashboard Cite

While chromium stable isotopes (δ 53 Cr) have received significant attention for their utility as a tracer of oxygen availability in the distant geological past, a mechanistic understanding of modern oceanic controls on Cr and δ 53 Cr is still lacking. Here we present total dissolved δ 53 Cr, concentrations of Cr (III) and total dissolved Cr, and net community productivity (NCP) from the North Pacific. Chromium concentrations show surface depletions in waters with elevated NCP, but not in lower productivity waters. Observed Cr deficits correspond well with calculated Cr export derived from NCP and Cr:C ratios of natural phytoplankton and marine particulates. Chromium (III) concentrations are stable over the diel cycle yet correlate with NCP, with maxima found in highly productive surface waters but not in lower productivity waters, indicating biological control on Cr (III). The relationship between Cr (III) and δ 53 Cr suggests that δ 53 Cr distributions may be controlled by the removal of isotopically light Cr (III) at an isotopic enrichment factor ( 53 Cr) of −1.08‰ ± 0.25 relative to total dissolved δ 53 Cr, in agreement with the global δ 53 Cr-Cr fractionation factor (−0.82‰ ± 0.05). No perturbation to δ 53 Cr, Cr, or Cr (III) is observed in oxygen-depleted waters (~10 μmol/kg), suggesting no strong control by O 2 availability, in agreement with other recent studies. Therefore, we propose that biological productivity is the primary control on Cr and δ 53 Cr in the modern ocean. Consequently, δ 53 Cr records in marine sediments may not faithfully record oxygen availability in the Late Quaternary. Instead, our data demonstrate that δ 53 Cr records may be a useful tracer for biological productivity.

show abstract

The Archean‐Proterozoic Boundary and the Great Oxidation Event

Gaucher

2018

Geophysical Monograph Series

View full text Add to dashboard Cite

INDEX Acidithiobacillus, 132 Amazon Craton biostratigraphy of, 102-4, 103f, 105f cap carbonate in southern, 98 contact between glacial deposits and cap carbonate in, 94, 97f Cryogenian-Ediacaran boundary in southern, 89-108, 90f, 92f, 95f-97f, 98f, 100f, 103f, 105f, 106f geological-structural setting of southern, 95f geologic map of southwestern, 90f global correlations with, 104-7, 105f, 106f insertion of post-Marinoan carbonates of, 106f lithostratigraphy and major geologic events of, 92f Marinoan cap carbonate in southern cap carbonate, 98-102, 98f, 100f cap dolostone, 99-101, 100f cap limestone cementstone, 101-2 Marinoan glacial deposits, 93-94, 95f, 96f paleobiology of, 102-4, 103f, 105f paleogeographic map for, 74f representative fossils of, 103f simplified stratigraphic section of glacial deposits with, 96f Ammonoids, 166 Angara Craton, 74f Anomaly, 29 Anticosti Island, 147f Apennines, 186f Araras Group acritarch specimens in, 104 carbon isotope chemostratigraphy for, 105f insertion of post-Marinoan carbonates of, 106f lithostratigraphy of, 105f microbial laminites in, 103 Aravalli-Bundelkhand Craton, 54-55, 54f, 59-60 Archean-Proterozoic boundary banded iron formation in, 35 BIF with, 42f chromium isotopes in, 39-40, 39f global change from, 35 Great Oxidation Event with, 9, 35-43, 36f, 38f, 39f, 41f, 42f molybdenum isotopes in, 40-41, 41f placement of, 42-43, 42f present atmospheric level exceeded by, 35, 37, 40-43 sulfur isotopes in, 36-38, 38f Arequipa Massif, 74f Argana Basin, 186f Argillaceous red, nodular, bioturbated wackestone, 166, 167f, 171f Aspidella, 131f Astartekløft, 192 Asteroid impact event, 224-25 Atar Group carbon isotope chemostratigraphy of, 80f Calcario Tangará quarry, 98f Calcium isotopes, 9-10 Calymmian period, 48, 51f, 52-53, 59, 64 depositional age for Dongchuan Group, 56 deposition of large red beds during, 61 sedimentary rocks of, 63 Calymmian rift, 47 Cambrian explosion, 123-24 CAMP. See Central Atlantic magmatic province Canada Ordovician paleogeographic position in, 147f Truro Island, Arctic in, 147f, 150-51, 152f Carbonate-associated sulfate (CAS) analyses in transitional Ediacaran to Cambrian successions, 123 composition of, 60 isotopic compositions of, 121-22 measurements of sulfur isotopes on, 8 Carbonate microfacies argillaceous red, nodular, bioturbated wackestone, 166, 167f, 171f gray/yellow nodular sponge wackestone, 166, 168f, 171f laminated bindstone, 166, 169f, 171f, 172f oncoid wackestone/floatstone, 166, 168, 170f, 172f Carbon isotopes, 5-6. See also Jurassic-Cretaceous carbon isotope geochemistry analysis and sampling strategies with, 165-66 Araras Group in chemostratigraphy with, 105f carbonate sequences data for, 58f, 59, 59f, 60 chemostratigraphy, 75f, 76f, 79f, 80f, 81f, 105f, 193, 194f-95f composition analysis results with, 172-74, 173f, 173t compositions in Mesoproterozoic-Neoproterozoic transition of, 81, 82f curves coupled with δ 53 Cr, 10, 12 Ediacaran-Cambrian transition, trends leading up to, 122 Permian-Triassic boundary with composition of, 160-62, ...

show abstract

Processes controlling the chromium isotopic composition of river water: Constraints from basaltic river catchments

Cited by 91 publications

References 71 publications

Cr isotopic insights into ca. 1.9 Ga oxidative weathering of the continents using the Beaverlodge Lake paleosol, Northwest Territories, Canada

Cr isotopic insights into ca. 1.9 Ga oxidative weathering of the continents using the Beaverlodge Lake paleosol, Northwest Territories, Canada

Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean

The Archean‐Proterozoic Boundary and the Great Oxidation Event

Contact Info

Product

Resources

About