Chromium isotope systematics in the Connecticut River

Wu, Weihua; Wang, Xiangli; Reinhard, Christopher T.; Planavsky, Noah J.

doi:10.1016/j.chemgeo.2017.03.009

Cited by 73 publications

(41 citation statements)

References 91 publications

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“…In this study, two basalt reference materials from the USGS, BHVO‐1 (−0.120 ± 0.029‰, 2 s ) and BHVO‐2 (−0.129 ± 0.032‰, 2 s ), gave slightly lower δ 53/52 Cr NIST SRM 979 values than that of peridotite reference material JP‐1 from JSG (−0.088 ± 0.034‰; 2 s ) with the mean results over a period of two years. The data obtained in this study for these basalt and peridotite reference materials are consistent with the δ 53/52 Cr NIST SRM 979 values reported by previous studies within the precision quoted (Schoenberg et al , , Wang et al , Li et al , , Gueguen et al , Bonnand et al , b, Wu et al , Xia et al , Zhu et al ) (Figure b).…”

Section: Resultssupporting

confidence: 92%

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High‐Precision Measurement of Stable Cr Isotopes in Geological Reference Materials by a Double‐Spike TIMS Method

Liu

et al. 2019

Geostandard Geoanalytic Res

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Chromium (Cr) isotopes have been widely used in various fields of Earth and planetary sciences. However, high‐precision measurements of Cr stable isotope ratios are still challenged by difficulties in purifying Cr and organic matter interference from resin using double‐spike thermal ionisation mass spectrometry. In this study, an improved and easily operated two‐column chemical separation procedure using AG50W‐X12 (200–400 mesh) resin is introduced. This resin has a higher cross‐linking density than AG50W‐X8, and this higher density generates better separation efficiency and higher saturation. Organic matter from the resin is a common cause of inhibition of the emission of Cr during analysis by TIMS. Here, perchloric and nitric acids were utilised to eliminate organic matter interference. The Cr isotope ratios of samples with lower Cr contents could be measured precisely by TIMS. The long‐term intermediate measurement precision of δ53/52CrNIST SRM 979 for BHVO‐2 is better than ± 0.031‰ (2s) over one year. Replicated digestions and measurements of geological reference materials (OKUM, MUH‐1, JP‐1, BHVO‐1, BHVO‐2, AGV‐2 and GSP‐2) yield δ53/52CrNIST SRM 979 results ranging from −0.129‰ to −0.032‰. The Cr isotope ratios of geological reference materials are consistent with the δ53/52CrNIST SRM 979 values reported by previous studies, and the measurement uncertainty (± 0.031‰, 2s) is significantly improved.

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Section: Resultssupporting

confidence: 92%

“…Comparison of geological reference material data analysed in this study (red symbols) with literature values (black symbols) (Schoenberg et al , , Gueguen et al . , Wang et al , Li et al , , Bonnand et al , b, Xia et al , Wu et al , Zhu et al ). [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Resultsmentioning

confidence: 99%

High‐Precision Measurement of Stable Cr Isotopes in Geological Reference Materials by a Double‐Spike TIMS Method

Liu

et al. 2019

Geostandard Geoanalytic Res

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“…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%

“…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%

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

et al. 2019

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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.

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A Versatile Cationic Organic Network Adsorbent for the Highly Efficient Removal of Diverse Water Contaminants

Zhang

Xue

et al. 2021

Adv Materials Inter

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Water decontamination is of great importance to address the increasing shortage of water resources, ion‐exchange‐driven adsorption being one of the most efficient approaches to this aim. Despite the advances achieved in this field, particularly with the emergence of ionic organic networks as a new class of adsorbents for water treatment, the development of adsorbents with high performance is still highly desired. This paper describes the facile preparation of a new cationic organic network, denoted as CON‐LDU3, via a quaternization reaction between 1,2,4,5‐tetra(pyridin‐4‐yl)benzene and 1,4‐bis(bromomethyl)benzene. The cationic framework and abundant exchangeable Br− anions render CON‐LDU3 as a suitable adsorbent to capture anionic contaminants from water. CON‐LDU3 displays fast kinetics and high capacity for the removal of CrO42−, reaching the kinetic constant and maximum capacity values of 0.0539 g mg−1 min−1 and 232 mg g−1, respectively. Moreover, this adsorbent can be regenerated by simple washing with KBr solution, and it can be recycled for at least eight times. CON‐LDU3 also exhibits excellent performance in the adsorption of some emerging organic water contaminants such as orange G and diclofenac sodium. Therefore, this study demonstrates the high potential of CON‐LDU3 as a versatile adsorbent for water remediation.

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Chromium isotope systematics in the Connecticut River

Cited by 73 publications

References 91 publications

High‐Precision Measurement of Stable Cr Isotopes in Geological Reference Materials by a Double‐Spike TIMS Method

High‐Precision Measurement of Stable Cr Isotopes in Geological Reference Materials by a Double‐Spike TIMS Method

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

A Versatile Cationic Organic Network Adsorbent for the Highly Efficient Removal of Diverse Water Contaminants

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