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Nambiar R, Kniest JF, Schmidt A, Raddatz J, Müller W, Evans D. Accurate measurement of K/Ca in low-[K] carbonate samples using laser-ablation sector-field inductively coupled plasma mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9692. [PMID: 38355885 DOI: 10.1002/rcm.9692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/10/2023] [Accepted: 12/06/2023] [Indexed: 02/16/2024]
Abstract
RATIONALE Potassium (K) is a major component of several silicate minerals and seawater, and, therefore, constraining past changes in the potassium cycle is a promising way of tracing large-scale geological processes on Earth. However, [K] measurement using inductively coupled plasma mass spectrometry (ICP-MS) is challenging due to an ArH+ interference, which may be of a similar magnitude to the K+ ion beam in samples with <0.1% m/m [K]. METHODS In this work, we investigated the effect of the ArH+ interference on K/Ca data quality by comparing results from laser-ablation (LA)-ICP-MS measured in medium and high mass resolution modes and validating our LA results via solution ICP-optical emission spectroscopy (OES) and solution ICP-MS measurements. To do so, we used a wide range of geological reference materials, with a particular focus on marine carbonates, which are potential archives of past changes in the K cycle but are typically characterised by [K] < 200 μg/g. In addition, we examine the degree to which trace-element data quality is driven by downhole fractionation during LA-ICP-MS measurements. RESULTS Our results show that medium mass resolution (MR) mode is sufficiently capable of minimising the effect of the ArH+ interference on K+ . However, the rate of downhole fractionation for Na and K varies between different samples as a result of their differing bulk composition, resulting in matrix-specific inaccuracy. We show how this can be accounted for via downhole fractionation corrections, resulting in an accuracy of better than 1% and a long-term reproducibility (intermediate precision) of <6% (relative standard deviation) in JCp-1NP using LA-ICP-MS in MR mode. CONCLUSION Our [K] measurement protocol is demonstrably precise and accurate and applicable to a wide range of materials. The measurement of K/Ca in relatively low-[K] marine carbonates is presented here as a key example of a new application opened up by these advances.
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Affiliation(s)
- Romi Nambiar
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Isotope and Element Research Center (FIERCE), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jorit F Kniest
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Isotope and Element Research Center (FIERCE), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Alexander Schmidt
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Isotope and Element Research Center (FIERCE), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jacek Raddatz
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Isotope and Element Research Center (FIERCE), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Wolfgang Müller
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Isotope and Element Research Center (FIERCE), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - David Evans
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Isotope and Element Research Center (FIERCE), Goethe University Frankfurt, Frankfurt am Main, Germany
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Xia Z, Li S, Hu Z, Bialik O, Chen T, Weldeghebriel MF, Fan Q, Fan J, Wang X, An S, Zhang F, Xu H, Chen J, Ji Z, Shen S, Lowenstein TK, Li W. The evolution of Earth's surficial Mg cycle over the past 2 billion years. SCIENCE ADVANCES 2024; 10:eadj5474. [PMID: 38427740 PMCID: PMC10906924 DOI: 10.1126/sciadv.adj5474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 01/26/2024] [Indexed: 03/03/2024]
Abstract
The surficial cycling of Mg is coupled with the global carbon cycle, a predominant control of Earth's climate. However, how Earth's surficial Mg cycle evolved with time has been elusive. Magnesium isotope signatures of seawater (δ26Mgsw) track the surficial Mg cycle, which could provide crucial information on the carbon cycle in Earth's history. Here, we present a reconstruction of δ26Mgsw evolution over the past 2 billion years using marine halite fluid inclusions and sedimentary dolostones. The data show that δ26Mgsw decreased, with fluctuations, by about 1.4‰ from the Paleoproterozoic to the present time. Mass balance calculations based on this δ26Mgsw record reveal a long-term decline in net dolostone burial (NDB) over the past 2 billion years, due to the decrease in dolomitization in the oceans and the increase in dolostone weathering on the continents. This underlines a previously underappreciated connection between the weathering-burial cycle of dolostone and the Earth's climate on geologic timescales.
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Affiliation(s)
- Zhiguang Xia
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation & Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China
- International Center for Sedimentary Geochemistry and Biogeochemistry Research, Chengdu University of Technology, Chengdu 610059, China
| | - Shilei Li
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
- Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences, Nanjing University, Nanjing 210023, China
| | - Zhongya Hu
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- State Key Laboratory of Marine Geology, School of Ocean and Earth Science, Tongji University, Shanghai 200092, China
| | - Or Bialik
- Institute of Geology and Palaeontology, University of Muenster, Corrensstr. 24, 48149 Münster, Germany
| | - Tianyu Chen
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Mebrahtu F. Weldeghebriel
- Department of Earth Sciences, Binghamton University, NY 13902, USA
- Department of Geosciences, Princeton University, NJ 08544, USA
| | - Qishun Fan
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
| | - Junxuan Fan
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Xiangdong Wang
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Shichao An
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Feifei Zhang
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Haoran Xu
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Jiayang Chen
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Zhihan Ji
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Shuzhong Shen
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
| | | | - Weiqiang Li
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, Jiangsu, China
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3
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Wang Q, Shan C, Zhang P, Zhao W, Zhu G, Sun Y, Wang Q, Jiang Y, Shakoor N, Rui Y. The combination of nanotechnology and potassium: applications in agriculture. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:1890-1906. [PMID: 38079036 DOI: 10.1007/s11356-023-31207-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 11/20/2023] [Indexed: 01/18/2024]
Abstract
Potassium fertilizer is indispensable for ensuring crop production, which in turn supports global food supply and safe farming practices. Potassium resources are primarily located in the Northern Hemisphere, leading to a current shortage of affordable potash and severe soil deficiencies in certain regions of the Southern Hemisphere. There is a shift away from mined salts in favor of locally available potassium resources. Utilizing potassium-rich silicates, for instance, could be a viable option to address this situation. The imperative of enhancing crop productivity and quality necessitates either increasing potassium availability or utilizing potassium more efficiently. Geneticists may find the development of plants that use potassium more effectively to be a valuable pursuit. Nanomaterials are increasingly becoming part of people's professional lives as a novel material category. This technology is gradually finding applications in agriculture to boost crop yields while reducing environmental pollution. This paper reviews the applications of common potassium-containing materials, explores the effects and mechanisms of nano-fertilizers on plants, and offers insights into future applications of nano-potassium fertilizers in agriculture. All in all, the application of nanotechnology in the production and utilization of potassium fertilizers is both necessary and effective. However, there are still many gaps in the current field of nano-potassium fertilizer application that require further research. It is hoped that this review can serve as a valuable reference for researchers working in this field.
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Affiliation(s)
- Qibin Wang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Chen Shan
- Department of Plant Nutrition, College of Resources and Environment, China Agricultural University, Beijing, 100193, China
| | - Peng Zhang
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Weichen Zhao
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Guikai Zhu
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yi Sun
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Quanlong Wang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yaqi Jiang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Noman Shakoor
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yukui Rui
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
- China Agricultural University Professor Workstation of Yuhuangmiao Town, Shanghe County, Jinan, Shandong, China.
- China Agricultural University Professor Workstation of Sunji Town, Shanghe County, Jinan, Shandong, China.
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An S, Chen J, Boschi S, Li W. Significantly Enhanced Robustness of K Isotope Analysis by Collision Cell MC-ICP-MS and Its Application to the Returned Lunar Samples by China's Chang'e-5 Project. Anal Chem 2023; 95:2140-2145. [PMID: 36652601 DOI: 10.1021/acs.analchem.2c03989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Stable K isotope ratios, an emerging research tool for a wide range of problems, can be measured precisely with high sensitivity by using collision cell multicollector ICP mass spectrometers (CC-MC-ICP-MS). However, it has been shown that the accuracy of K isotope analysis by CC-MC-ICP-MS could be compromised severely by trace-level Ca contaminants, although the cause of such an effect remains poorly understood. Here, we report that the influence of Ca on K isotope analysis by CC-MC-ICP-MS can be dramatically reduced if D2 rather than H2 (the default gas) is used as the reaction gas that goes into the collision cell. This indicates the generation of positively charged calcium-hydride molecules in the collision cell. Usage of D2 as reaction gas circumvents the Ca-induced inaccuracy issues during K isotope analysis because 40CaD+ does not interfere with 41K+ as 40CaH+ does; as such, the robustness of K isotope analysis by CC-MC-ICP-MS is significantly enhanced. This improved method is verified by K isotope analysis of seven geostandards, and applied to China's Chang'e-5 lunar return samples at submicrogram K consumption, revealing significant K isotope variability within a 17 mg lunar basalt fragment.
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Affiliation(s)
- Shichao An
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu210023, P. R. China.,Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing210023, P. R. China
| | - Jiayang Chen
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu210023, P. R. China.,Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing210023, P. R. China
| | - Samuele Boschi
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu210023, P. R. China.,Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing210023, P. R. China
| | - Weiqiang Li
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu210023, P. R. China.,Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing210023, P. R. China
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5
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An S, Luo X, Li W. Precise measurement of 41 K/ 39 K ratios by high-resolution multicollector inductively coupled plasma mass spectrometry under a dry and hot plasma setting. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022; 36:e9289. [PMID: 35262246 DOI: 10.1002/rcm.9289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/27/2022] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
Abstract
RATIONALE Stable K isotope geochemistry is becoming an important tool for various applications. Developments in analytical methods for K isotopes based on multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) without collision cell will bring research capability of K isotopes to many existing MC-ICP-MS labs. METHODS Stable K isotopes were analyzed without applications of "cold plasma" and collision cell on a Nu 1700 Sapphire high-resolution multicollector inductively coupled plasma mass spectrometer. A conventional dry and hot plasma setting is used for analysis to maintain high K sensitivity and signal stability, and high mass resolution was applied to provide interference-free shoulders of 39 K+ for isotopic measurement of 41 K/39 K ratios. 40 Ar+ ion beam generated in ICP was neutralized in the ion guide rail for the Daly detector. RESULTS Under such operating conditions, an external reproducibility of <±0.1‰ (2 standard deviation) for 41 K/39 K is achieved for K solutions of 1 ppm or above. Tests were carried out to evaluate the influence of total K loading, K concentration and acid molarity mismatch, matrix effects, and 40 Ar+ and 40 Ar1 H+ tailing on K isotope analysis. We found that the accuracy of K isotope analysis can be compromised by concentration mismatch of sample and standard K, by 0.007‰ in δ41 K per 1% mismatch of K content. By contrast, mismatch of HNO3 molarity or existence of HCl in HNO3 exerts negligible influences on the analytical precision and accuracy of K isotope analysis. Furthermore, K isotope analytical results remain accurate when Na/K, Mg/K, Ca/K, Rb/K, V/K, and Cr/K ratios are below 3%. CONCLUSIONS The high-precision K isotope analytical method reported here is robust for studies on K isotopic variations in geological, cosmochemical, and biological samples. The f41 K values of six international geostandards measured using our method are consistent with data measured using different analytical methods from other laboratories.
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Affiliation(s)
- Shichao An
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, China
| | - Xianglong Luo
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, China
| | - Weiqiang Li
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing
- Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, China
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6
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Zhang T, Mao S, Sun P, Gao X, Fang H, Luo H, Zhang W, Zhou B. Nanosized FeS/ZnS heterojunctions derived using zeolitic imidazolate Framework-8 (ZIF-8) for pH-universal oxygen reduction and High-efficiency Zn-air battery. J Colloid Interface Sci 2022; 608:446-458. [PMID: 34626988 DOI: 10.1016/j.jcis.2021.09.134] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 12/13/2022]
Abstract
Low-cost, stable, and highly active electrocatalysts for oxygen reduction reaction (ORR), especially for pH-universal ORR, are vital for developing numerous renewable energy devices. Herein, a hierarchical N, S-codoped porous carbon-based catalyst (ZFP-800) coupled with abundant FeS/ZnS heterojunctions was facilely prepared via direct pyrolysis of a Ferrocene-crosslinked pyrrole hydrogel composited with zeolitic imidazolate framework-8 (ZIF-8) templates. Compared with the heterojunction-free catalytic activity, the ZFP-800 catalytic activity was significantly higher in pH-universal ranges. Moreover, the ZFP-800 exhibited competitive ORR performance to commercial Pt/C (20%) in various electrolytes, in terms of onset (Eonset), half-wave potentials (E1/2), limiting current density (JL), durability, and methanol immunity. For instance, it exhibited super ORR catalytic activity on Eonset and E1/2, and exceeded that of the benchmark Pt/C in both the alkaline and neutral media. Furthermore, the application of ZFP-800 as a cathode catalyst in a home-made Zn-air battery demonstrated its operation capability in ambient conditions with a competitive performance on the specific energy density (828 mA·h·gZn-1), maximum discharge power density (205.6 mW·cm-2), rate performance, and the long-term stability (188 h at 5 mA·cm-2). This study can facilitate the development of advanced heterojunction-based materials for renewable energy applications.
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Affiliation(s)
- Teng Zhang
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China
| | - Shumei Mao
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China
| | - Peng Sun
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China
| | - Xiaoyi Gao
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China
| | - Hui Fang
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China
| | - Haotian Luo
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China
| | - Weifen Zhang
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China
| | - Baolong Zhou
- School of Pharmacy, Weifang Medical University, Weifang, Shandong 261053, PR China.
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Wilson Kuhnel W, Jacobsen SB, Li Y, Ku Y, Petaev MI, Huang S, Wu Z, Wang (王昆) K. High-temperature inter-mineral potassium isotope fractionation: implications for K-Ca-Ar chronology. ACS EARTH & SPACE CHEMISTRY 2021; 5:2740-2754. [PMID: 35005332 PMCID: PMC8740525 DOI: 10.1021/acsearthspacechem.1c00147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Recent advances in high-precision potassium (K) isotopic analysis have found considerable isotopic variation in rock samples of the Earth's continental and oceanic crusts; however, it is still uncertain whether there is any resolvable inter-mineral and mineral-melt K isotopic fractionation during igneous and metamorphic processes. Here, we report K isotope compositions of mineral separates from three extremely well preserved igneous rocks (intrusive/extrusive and mafic/intermediate/felsic) in order to investigate possible inter-mineral and mineral-melt K isotopic fractionation at magmatic temperatures. For the first time, we found large inter-mineral fractionation of K isotopes in natural samples (up to 1.072‰), where plagioclase displays a significant enrichment of heavier K isotopes compared to potassium feldspar and biotite in a granite. In addition, we also observed smaller but measurable K isotope fractionation (0.280‰±0.030‰) between ternary feldspar phenocrysts and matrix in a trachyandesite, as well as a comparable isotope fractionation (0.331‰±0.010‰) between plagioclase and the bulk in a gabbroic intrusive rock. We also evaluated such results by comparing the theoretically calculated equilibrium K isotope fractionation factors between relevant igneous minerals in literature and this study. In general, the measured inter-mineral fractionations are consistent with the theoretical calculations (i.e., plagioclase is enriched in heavier isotopes compared to potassium feldspar). Specifically, the measured K isotope fractionation between phenocryst rim and matrix in the trachyandesite agrees well with the calculated equilibrium isotope fractionation. However, the measured K isotope fractionations between phenocryst core and matrix as well as between plagioclase and K-feldspar are significantly larger (by a factor of ~2-3) than the calculated isotope fractionations, which suggest isotopic disequilibrium due to kinetic processes. Using a range of plagioclase-melt isotope fractionation factors inferred from the theoretical calculations in this study, we modeled the K isotopic fractionation during the formation of lunar anorthositic crust, and the result shows a negligible effect on the K isotopic compositions in both lunar crust and mantle. The K isotopic difference between Earth and Moon, therefore, cannot be the result of Lunar Magma Ocean differentiation. Finally, we evaluate the effect of observed inter-mineral fractionations on K-Ar and 40Ar-39Ar dating. This study indicates the variation of 40K/K ratio would contribute a maximum 0.08% error to the K-Ar and 40Ar-39Ar age uncertainties. We propose a refined 40K/total K ratio as 0.00011664±0.00000011 (116.64±0.11ppm) instead of the conventional value, 0.0001167(2) for the present Earth. Because some minerals fractionate K isotopes, ultrahigh precision age dating with the K-Ca-Ar dating systems must measure the K isotope fractionation in the same mineral fractions used for age dating.
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Affiliation(s)
- W. Wilson Kuhnel
- Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA
| | - Stein B. Jacobsen
- Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA
| | - Yonghui Li
- Laboratory of Seismology and Physics of Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yaray Ku
- Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA
| | - Michail I. Petaev
- Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA
| | - Shichun Huang
- Department of Geoscience, University of Nevada, Las Vegas, NV 89154, USA
| | - Zhongqing Wu
- Laboratory of Seismology and Physics of Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Kun Wang (王昆)
- Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
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Neogene continental denudation and the beryllium conundrum. Proc Natl Acad Sci U S A 2021; 118:2026456118. [PMID: 34649990 DOI: 10.1073/pnas.2026456118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2021] [Indexed: 11/18/2022] Open
Abstract
Reconstructing Cenozoic history of continental silicate weathering is crucial for understanding Earth's carbon cycle and greenhouse history. The question of whether continental silicate weathering increased during the late Cenozoic, setting the stage for glacial cycles, has remained controversial for decades. Whereas numerous independent proxies of weathering in ocean sediments (e.g., Li, Sr, and Os isotopes) have been interpreted to indicate that the continental silicate weathering rate increased in the late Cenozoic, beryllium isotopes in seawater have stood out as an important exception. Beryllium isotopes have been interpreted to indicate stable continental weathering and/or denudation rates over the last 12 Myr. Here we present a Be cycle model whose results show that variations in the 9Be weathering flux are counterbalanced by near-coastal scavenging while the cosmogenic 10Be flux from the upper atmosphere stays constant. As a result, predicted seawater 10Be/9Be ratios remain nearly constant even when global denudation and Be weathering rates increase by three orders of magnitude. Moreover, 10Be/9Be records allow for up to an 11-fold increase in Be weathering and denudation rates over the late Cenozoic, consistent with estimates from other proxies. The large increase in continental weathering indicated by multiple proxies further suggests that the increased CO2 consumption by continental weathering, driven by mountain-building events, was counterbalanced by other geological processes to prevent a runaway icehouse condition during the late Cenozoic. These processes could include enhanced carbonate dissolution via pyrite weathering, accelerated oxidation of fossil organic carbon, and/or reduced basalt weathering as the climate cooled.
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Potassium isotope composition of Mars reveals a mechanism of planetary volatile retention. Proc Natl Acad Sci U S A 2021; 118:2101155118. [PMID: 34544856 DOI: 10.1073/pnas.2101155118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2021] [Indexed: 11/18/2022] Open
Abstract
The abundances of water and highly to moderately volatile elements in planets are considered critical to mantle convection, surface evolution processes, and habitability. From the first flyby space probes to the more recent "Perseverance" and "Tianwen-1" missions, "follow the water," and, more broadly, "volatiles," has been one of the key themes of martian exploration. Ratios of volatiles relative to refractory elements (e.g., K/Th, Rb/Sr) are consistent with a higher volatile content for Mars than for Earth, despite the contrasting present-day surface conditions of those bodies. This study presents K isotope data from a spectrum of martian lithologies as an isotopic tracer for comparing the inventories of highly and moderately volatile elements and compounds of planetary bodies. Here, we show that meteorites from Mars have systematically heavier K isotopic compositions than the bulk silicate Earth, implying a greater loss of K from Mars than from Earth. The average "bulk silicate" δ41K values of Earth, Moon, Mars, and the asteroid 4-Vesta correlate with surface gravity, the Mn/Na "volatility" ratio, and most notably, bulk planet H2O abundance. These relationships indicate that planetary volatile abundances result from variable volatile loss during accretionary growth in which larger mass bodies preferentially retain volatile elements over lower mass objects. There is likely a threshold on the size requirements of rocky (exo)planets to retain enough H2O to enable habitability and plate tectonics, with mass exceeding that of Mars.
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Ionov DA, Wang K. Potassium distribution and isotope composition in the lithospheric mantle in relation to global Earth's reservoirs. GEOCHIMICA ET COSMOCHIMICA ACTA 2021; 309:151-170. [PMID: 35001942 PMCID: PMC8739498 DOI: 10.1016/j.gca.2021.06.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Recent analytical advances have provided means to measure potassium (K) isotopes in various terrestrial materials, but little is known about K distribution and stable isotope composition in the lithospheric mantle because of: (a) common low K abundances, (b) potential contamination and alteration, (c) diversity of mantle rocks and minerals hosting K in different tectonic settings. We report K abundances and δ41K values for well-studied whole-rock (WR) mantle xenoliths (spinel and garnet peridotites and pyroxenites) from mobile belts, a craton, a subduction zone, as well as for K-rich phases (mica, amphibole, silicate glass) and xenolith-bearing volcanic materials (67 samples). The xenolith materials show extremely broad ranges of K content (7 μg/g to 6.6 wt.%) and δ41K (-2.77‰ to 0.62‰). They contrast with the narrow δ41K range for host volcanic materials (-0.53‰ to -0.27‰) and literature data on oceanic basalts (melting products of upwelling asthenosphere: -0.43 ± 0.17‰, 2sd). Amphibole-bearing subduction zone peridotites show the highest WR δ41K values (0.40 to 0.62‰) likely inherited from fluids released into the mantle wedge from subducted oceanic crust. All other WR samples yield negative δ41K: -0.06‰ to -2.77‰ for peridotites and -0.17‰ to -0.52‰ for pyroxenites. The δ41K in K-rich mantle phases range from positive values (0.16 to 0.57‰) for phlogopite in strongly metasomatized peridotites to negative values (-0.27 to -0.94‰) for phlogopite, amphibole and glass pockets from other samples, which cannot be explained by equilibrium inter-mineral fractionation inferred from ab initio calculations. We attribute the broad δ41K variations to (a) isotope fractionation during fluid-rock interaction in the mantle, and (b) distinct sources of K-bearing fluids. Kinetic isotope fractionation during fluid percolation and diffusion is inferred for composite xenoliths (phlogopite and pyroxenite veins in peridotites) that have lower δ41K in the hosts than in the veins due to slower migration of 41K than 39K from the veins (former fluid channels) to host mantle. Overall, the K isotope fractionation in the lithospheric mantle appears to be greater than for magmatic fractionation in the crust. The average δ41K of normal off-craton continental lithospheric mantle calculated from the least altered fertile and lightly metasomatized lherzolites is -0.57 ± 0.28‰ (2sd). This value is within error (though a little lower) of estimates for both continental crust and MORB and OIB mantle sources indicating that these major silicate Earth reservoirs have similar bulk δ41K values, apparently due to low or negligible K isotopic fractionation during their formation by magmatic differentiation and melting. By contrast, K isotopes in modern and fossil subduction zones are fractionated via fluid-related equilibrium and kinetic processes.
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Affiliation(s)
- Dmitri A. Ionov
- Géosciences Montpellier, Université de Montpellier, 34095 Montpellier, France
| | - Kun Wang
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA
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Wang K, Li W, Li S, Tian Z, Koefoed P, Zheng XY. Geochemistry and Cosmochemistry of Potassium Stable Isotopes. CHEMIE DER ERDE : BEITRAGE ZUR CHEMISCHEN MINERALOGIE, PETROGRAPHIE UND GEOLOGIE 2021; 81:125786. [PMID: 35001939 PMCID: PMC8740523 DOI: 10.1016/j.chemer.2021.125786] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Stable potassium isotopes are one of the emerging non-traditional isotope systems enabled in recent years by the advance of Multi-Collector Inductively-Coupled-Plasma Mass-Spectrometry (MC-ICP-MS). In this review, we first summarize the geochemical and cosmochemical properties of K, its major reservoirs, and the analytical methods of K isotopes. Following this, we review recent literature on K isotope applications in the fields of geochemistry and cosmochemistry. Geochemically, K is a highly incompatible lithophile element, and a highly soluble, biophile element. The isotopic fractionation of K is relatively small during magmatic processes such as partial melting and fractional crystallization, whereas during low-temperature and biological processes fractionation is considerably larger. This resolvable fractionation has made K isotopes promising tracers for a variety of Earth and environmental processes, including chemical weathering, low-temperature alteration of igneous rocks, reverse weathering, and the recycling of sediments into the mantle during subduction. Sorption and interactions of aqueous K with different clay minerals during cation exchange and clay formation are likely to be of fundamental significance in generating much of the K isotope variability seen in samples from the Earth surface and samples carrying recycled surface materials from the deep Earth. The magnitude of this fractionation is process- and mineral-dependent. Comprehensive quantification of pertinent K isotope fractionation factors is currently lacking and urgently needed. Significant fractionation during biological activities, such as plant uptake, demonstrates the potential utility of K isotopes in the study of the nutrient cycle and its relation to the climate and various ecosystems, enabling new and largely unexplored avenues for future research. Of significant importance to the cosmochemistry community, K is a moderately volatile element with large variations in K/U ratio observed among chondrites and planetary materials. As this indicates different degrees of volatile depletion, it has become a fundamental chemical signature of both chondritic and planetary bodies. This volatile depletion has been attributed to various processes such as solar nebula condensation, mixing of volatile-rich and -poor reservoirs, planetary accretional volatilization via impacts, and/or magma ocean degassing. While K isotopes have the potential to distinguish these different processes, the current results are still highly debated. A good correlation between the K isotope compositions of four differentiated bodies (Earth, Mars, Moon, and Vesta) and their masses suggests a ubiquitous volatile depletion mechanism during the formation of the terrestrial planets. It is still unknown whether any of the K isotopic variation among chondrites and differentiated bodies can be attributed to inherited signatures of mass-independent isotopic anomalies.
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Affiliation(s)
- Kun Wang
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, MO 63130, USA
| | - Weiqiang Li
- School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Shilei Li
- School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Zhen Tian
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, MO 63130, USA
| | - Piers Koefoed
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, MO 63130, USA
| | - Xin-Yuan Zheng
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
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Cui J, Tcherkez G. Potassium dependency of enzymes in plant primary metabolism. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 166:522-530. [PMID: 34174657 DOI: 10.1016/j.plaphy.2021.06.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
Potassium is a macroelement essential to many aspects of plant life, such as photosynthesis, phloem transport or cellular electrochemistry. Many enzymes in animals or microbes are known to be stimulated or activated by potassium (K+ ions). Several plant enzymes are also strictly K+-dependent, and this can be critical when plants are under K deficiency and thus intracellular K+ concentration is low. Although metabolic effects of low K conditions have been documented, there is presently no review focusing on roles of K+ for enzyme catalysis or activation in plants. In this mini-review, we compile the current knowledge on K+-requirement of plant enzymes and take advantage of structural data to present biochemical roles of K+. This information is instrumental to explain direct effects of low K+ content on metabolism and this is illustrated with recent metabolomics data.
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Affiliation(s)
- Jing Cui
- Research School of Biology, ANU Joint College of Sciences, Australian National University, 2601, Canberra, Australia
| | - Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Sciences, Australian National University, 2601, Canberra, Australia; Institut de Recherche en Horticulture et Semences, INRAe Angers, Université d'Angers, 42 rue Georges Morel, 49070, Beaucouzé, France.
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Hu Y, Teng FZ, Plank T, Chauvel C. Potassium isotopic heterogeneity in subducting oceanic plates. SCIENCE ADVANCES 2020; 6:eabb2472. [PMID: 33268367 PMCID: PMC7821876 DOI: 10.1126/sciadv.abb2472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 10/19/2020] [Indexed: 05/27/2023]
Abstract
Oceanic crust and sediments are the primary K sinks for seawater, and they deliver considerable amounts of K to the mantle via subduction. Historically, these crustal components were not studied for K isotopes because of the lack of analytical precision to differentiate terrestrial variations. Here, we report a high-precision dataset that reveals substantial variability in oceanic plates and provides further insights into the oceanic K cycle. Sixty-nine sediments worldwide yield a broad δ41K range from -1.3 to -0.02‰. The unusually low values are indicative of release of heavy K during continental weathering and uptake of light K during submarine diagenetic alteration. Twenty samples of altered western Pacific crust from ODP Site 801 display δ41K from -0.60 to -0.05‰, averaging at -0.32‰. Our results indicate that submarine alteration of oceanic plates is essential for generating the high-δ41K signature of seawater. These regionally varying subducting components are heterogeneous K inputs to the mantle.
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Affiliation(s)
- Yan Hu
- Isotope Laboratory, Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA.
| | - Fang-Zhen Teng
- Isotope Laboratory, Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA.
| | - Terry Plank
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964-8000, USA
| | - Catherine Chauvel
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France
- Université Grenoble Alpes, ISTerre, CNRS, F-38041 Grenoble, France
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Hille M, Hu Y, Huang TY, Teng FZ. Homogeneous and heavy potassium isotopic composition of global oceans. Sci Bull (Beijing) 2019; 64:1740-1742. [PMID: 36659530 DOI: 10.1016/j.scib.2019.09.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/01/2019] [Accepted: 09/03/2019] [Indexed: 01/21/2023]
Affiliation(s)
- Madeline Hille
- Isotope Laboratory, Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195-1310, USA
| | - Yan Hu
- Isotope Laboratory, Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195-1310, USA
| | - Tian-Yi Huang
- Isotope Laboratory, Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195-1310, USA
| | - Fang-Zhen Teng
- Isotope Laboratory, Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195-1310, USA.
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