A 13 million-year record of Li isotope compositions in island carbonates: Constraints on bulk inorganic carbonate as a global seawater Li isotope archive

Wei, Guang‐Yi; Zhang, Feifei; Yin, Yisheng; Lin, Yibo; Strandmann, Philip A.E. Pogge von; Cao, Mengchun; Li, Na; Xiong, Guolin; Chen, Xinran; Fan, Caiwei; Xu, Cheng; Tan, Fei; Zhang, Xiyang; Yang, Hongqiang; Ling, Hong-Fei; Shen, Shu-zhong

doi:10.1016/j.gca.2023.01.013

Cited by 12 publications

(5 citation statements)

References 82 publications

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“…) (30.22±0.15‰, n=7) were similar to published data within uncertainty. 1,3,4,15,24,29,33,[53][54][55][56][57][58][59][60][61][62][63] We also dissolved SCo-1 with 2 mol L -1 HCl, the obtained δ 7 Li values of SCo-1 is similar to the reported values of -1.90±0.20‰ by Li et al (Table 3) 54 Li isotope of SCo-1 depends on the acids used for digestion. Both Li isotope of the whole rock and the carbonate component agree with those reported in the literature.…”

Section: Accurate Determination Of LI Isotopes For Natural Materialssupporting

confidence: 78%

Purification of High Aluminum Content Samples for Rapid and Precise Analysis of Lithium Isotopes

Zhu

2023

At.Spectrosc.

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The analysis of lithium isotopes in high-aluminum content samples was accompanied by significant tailing of Al on Li using the traditional single-column method regardless of using single HCl or HNO3 as eluent. This hindered the precise determination of Li isotopes and made one-step column chromatographic separation of Li in silicate rocks challenging. Additional column procedures may be required to separate Li from Al in high Al samples, which would be time-consuming and result in reagent waste. In this study, the use of a 10 mL 0.2 mol L -1 HF and 0.5 mol L -1 HCl mixed eluent significantly reduced the Al tailing to less than 1% of that observed with the traditional method. The proposed purification procedure is applicable to a wide range of geological samples or minerals (e.g., silicates, seawater, sediments, and feldspars). Additionally, the matrix effect of Al and the Li concentration effect were investigated for accurate Li isotope analysis. The concentration effect, which was proved mainly led by the inappropriate treatment of the baseline. The real concentration effect yielded only a bias of 0.2‰ if normalized the solution of 20 ng g -1 Li with that of 140 ng g -1 . In accounting for this, Li isotopes can now be analyzed quite accurately at variable concentrations during non-strictly concentration-matched conditions. The longterm external precision of δ 7 Li based on the international standard LSVEC was approximately ±0.2‰ (2SD), making it suitable for geological sample analyses. The proposed method was confirmed through the analysis of BCR-2, BHVO-2, AGV-2, BIR-1a, RGM-2, JF-1, SCo-1, GSP-2, GSR-6, and GSR-8. All the results agreed with previously published values. Besides, two in-house Li isotope solution standards CAGS-Li-P (6.25±0.25‰) and CAGS-Li-N (-15.02±0.18‰) were developed and routinely analyzed to monitor the instrumental mass bias.

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Section: Accurate Determination Of LI Isotopes For Natural Materialssupporting

confidence: 78%

Purification of High Aluminum Content Samples for Rapid and Precise Analysis of Lithium Isotopes

Zhu

2023

At.Spectrosc.

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“…The LMS section yields low values for Al/Ca (<0.8 mmol/mol) and Li/Ca (1–8 μmol/mol), and no correlation is observed between these ratios and δ 7 Li carb (Figures S2a and S2b in Supporting Information ), indicating that silicate clays have not significantly influenced measured δ 7 Li carb values (Pogge von Strandmann et al., 2013). Study of modern systems indicates that meteoric and marine fluid‐buffered diagenesis would induce significant (positive or negative) correlations between δ 7 Li and Li/Ca, Sr/Ca and δ 13 C, which can be used to evaluate whether measured δ 7 Li carb reflects changes in contemporaneous seawater composition (Dellinger et al., 2020; Wei et al., 2023). No observable correlations were identified among these proxies (Figures S2b–S2d in Supporting Information ), suggesting no or minimal burial digenetic overprinting of the δ 7 Li carb profile of the LMS section.…”

Section: Resultsmentioning

confidence: 99%

“…, 2013). Study of modern systems indicates that meteoric and marine fluid-buffered diagenesis would induce significant (positive or negative) correlations between δ 7 Li and Li/Ca, Sr/Ca and δ 13 C, which can be used to evaluate whether measured δ 7 Li carb reflects changes in contemporaneous seawater composition (Dellinger et al, 2020;Wei et al, 2023). No observable correlations were identified among these proxies (Figures S2b-S2d in Supporting Information S1), suggesting no or minimal burial digenetic overprinting of the δ 7 Li carb profile of the LMS section.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Continental Weathering as a Trigger for the End‐Devonian Hangenberg Crisis

Qie

Zhang

Luo

et al. 2023

Geophysical Research Letters

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The Hangenberg Crisis coincided with a large decline of biodiversity and widespread anoxia in the end‐Devonian ocean. Previous research attributed marine anoxia to the spread of deeply‐rooted plants and/or increased volcanism on the continents, but crucial links have not been thoroughly explored. Herein, we propose enhanced weathering as a key trigger, as evidenced by a negative shift (∼8‰) in lithium isotopes and a coupled response in carbon isotopes of marine carbonates in South China. Our findings imply that rapid weathering of crustal rocks increased nutrient delivery to the ocean, as indicated by an increase in the carbonate‐associated phosphate levels, contributing to oceanic eutrophication. In the absence of massive volcanic emissions and intense orogeny, the cause of enhanced continental weathering was likely the expansion of the terrestrial rhizosphere, highlighting the potential for land plant evolution to initiate weathering changes of sufficient severity to trigger a major bio/environmental crisis in the Earth system.

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“…The formation of micrite typically occurs during burial diagenesis. In shallow marine carbonates, marine burial diagenesis and dolomitization have no significant impact on the Li isotope composition of the carbonates as long as they are under fluid‐buffered conditions (Dellinger et al., 2020; Wei et al., 2023). Otherwise, the Li isotope composition will decrease toward lower values.…”

Section: Discussionmentioning

confidence: 99%

“…Like for every other geochemical proxy, diagenesis may alter the Li isotope composition of fossil carbonates. Dellinger et al (2020) and Wei et al (2023) investigated the influence of meteoric diagenesis, burial diagenesis and dolomitization on shallow marine platform carbonates. Thereby, they observed that the recrystallization of aragonite into low-Mg calcite during meteoric diagenesis causes a decrease in Li/(Ca + Mg) as well as a shift to lower δ 7 Li carbonate compositions.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Chalk as an Archive for the Lithium Isotope Composition of Seawater

Huber,

Schlidt,

Seitz

et al. 2024

Geochem Geophys Geosyst

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The understanding of silicate weathering and its role as a sink for atmospheric CO2 is important to get a better insight into how the Earth shifts from warm to cool climates. The lithium isotope composition (δ7Li) of marine carbonates can be used as a proxy to track the past chemical weathering of silicates. A high‐resolution δ7Li record would be helpful to evaluate the role of silicate weathering during the late Cretaceous climate cooling. Here, we assess chalk as a potential archive for reconstructing Late Cretaceous seawater Li isotope composition by comparing Maastrichtian chalk from Northern Germany (Hemmoor, Kronsmoor) to a Quaternary coccolith ooze from the Manihiki Plateau (Pacific Ocean) as a lithological analog to modern conditions. We observe a negative offset of 3.9 ± 0.6‰ for the coccolith ooze relative to the modern seawater Li isotope composition (+31.1 ± 0.3‰; 2SE; n = 54), a value that falls in the range of published offsets for modern core‐top samples and for brachiopod calcite. Further, the negative offset between the Li isotope compositions of Manihiki coccolith ooze and modern planktonic foraminifera is 2.3 ± 0.6‰. Although chalk represents a diagenetically altered modification of pelagic nannofossil ooze, manifested by changes in the composition of trace elements, we observe a consistent offset of Li isotope data between Maastrichtian chalk and Maastrichtian planktonic foraminiferal data (−1.4 ± 0. 5‰) that lies within the uncertainty of modern values. We therefore suggest that chalk can be used as a reliable archive for δ7Li reconstructions.

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A 13 million-year record of Li isotope compositions in island carbonates: Constraints on bulk inorganic carbonate as a global seawater Li isotope archive

Cited by 12 publications

References 82 publications

Purification of High Aluminum Content Samples for Rapid and Precise Analysis of Lithium Isotopes

Purification of High Aluminum Content Samples for Rapid and Precise Analysis of Lithium Isotopes

Enhanced Continental Weathering as a Trigger for the End‐Devonian Hangenberg Crisis

Assessment of Chalk as an Archive for the Lithium Isotope Composition of Seawater

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