Lithium isotope systematics in a forested granitic catchment (Strengbach, Vosges Mountains, France)

Lemarchand, Emmanuel; Chabaux, François; Vigier, Nathalie; Millot, Romain; Pierret, Marie‐Claire

doi:10.1016/j.gca.2010.04.057

Cited by 153 publications

(120 citation statements)

References 49 publications

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“…Such elevated d Li in some samples of the Hawaiian climosequence, but they were clearly controlled by marine aerosols. The upper horizons of the 1400 and 4100 ka sites are enriched in organic matter (Table S1), but as a first approximation, we can rule out a key role of vegetation because of low Li levels in plants and the lack of associated isotope fractionation (Lemarchand et al, 2010). Since the surface soil horizons have lost some Li compared to younger soils (Fig.…”

Section: Controls Of LI Isotope Fractionation During Basalt Alterationmentioning

confidence: 93%

Variation of lithium isotope geochemistry during basalt weathering and secondary mineral transformations in Hawaii

Ryu

Vigier

Lee

et al. 2014

Geochimica et Cosmochimica Acta

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Lithium isotopes are a potential tracer of silicate weathering but the relationship between lithium isotope compositions and weathering state still need to be established with precision. Here, we report Li concentrations and Li isotope compositions of soils developed along a 4 million year humid-environment chronosequence in the Hawaiian Islands. Li concentrations are variable with depth and age, ranging from 0.24 to 21.3 ppm, and significant Li depletions (up to 92%) relative to parent basalts are systematically enhanced towards the surface. Our calculations show that the relative contribution from atmospheric deposits to the Li soil budget remains small, with a maximum contribution from dust Li of 20% at the oldest site. This is explained by the capacity of the weathering products to retain, within the profiles, the Li coming from basalt alteration, and allows us to explore more specifically the role of alteration processes on soil Li isotope signatures. The d Li values for the older soils (P20 ka) vary non-linearly as a function of time and can be explained by progressive mineral transformations starting with the synthesis of metastable short-range order (nano-crystalline) minerals and followed by their transformation into relatively inert secondary minerals. Results highlight significant Li isotope fractionation during secondary mineral formation and in particular during Li uptake by kaolinite. Finally, we suggest that the non-monotonous evolution of the regolith d 7 Li value over the last 4 Ma is consistent with climatic variations, where congruent release of Li isotopes occurs during warmer periods.

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Section: Controls Of LI Isotope Fractionation During Basalt Alterationmentioning

confidence: 93%

Variation of lithium isotope geochemistry during basalt weathering and secondary mineral transformations in Hawaii

Ryu

Vigier

Lee

et al. 2014

Geochimica et Cosmochimica Acta

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“…Hence, the  7 Li of rivers is controlled by the ratio of primary mineral dissolution to secondary mineral formation, which can be defined as the weathering congruency or intensity (Dellinger et al, 2015;Kisakürek et al, 2005;Liu et al, 2015;Misra & Froelich, 2012;Pogge von Strandmann et al, 2013. The global mean riverine  7 Li today is about 23‰ (Huh et al, 1998) with values extending between 1.2 and 43% (Dellinger et al, 2015;Huh et al, 2001;Kisakurek et al, 2005;Lemarchand et al, 2010;Liu et al, 2015;Pogge von Strandmann & Henderson, 2015;Pogge von Strandmann et al, 2010, 2006Vigier et al, 2009).…”

Section: Weathering and The Li-isotope Composition Of The Oceansmentioning

confidence: 99%

Lithium-isotope evidence for enhanced silicate weathering during OAE 1a (Early Aptian Selli event)

Lechler

Strandmann

Jenkyns

et al. 2015

Earth and Planetary Science Letters

113

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An abrupt rise in temperature, forced by a massive input of CO 2 into the atmosphere, is commonly invoked as the main trigger for Oceanic Anoxic Events (OAEs). Global warming initiated a cascade of palaeoenvironmental perturbations starting with increased continental weathering and an accelerated hydrological cycle that delivered higher loads of nutrients to coastal areas, stimulating biological productivity.The end-result was widespread anoxia and deposition of black shales: the hallmarks of OAEs. In order to assess the role of weathering as both an OAE initiator and terminator (via CO 2 sequestration) during the Early Aptian OAE 1a (Selli Event, ~120 Ma) the isotopic ratio of lithium isotopes was analysed in three sections of shallowmarine carbonates from the Pacific and Tethyan realm and one basinal pelagic section from the Tethyan domain. Because the isotopic composition of lithium in seawater is largely controlled by continental silicate weathering and high-and lowtemperature alteration of basaltic material, a shift to lighter  7 Li values is expected to characterize OAEs. The studied sections illustrate this phenomenon:  7 Li values decrease to a minimum coincident with the negative carbon-isotope excursion that effectively records the onset of OAE 1a. A second negative  7 Li excursion occurs coeval with the minimum in strontium isotopes after the event. The striking similarity to the strontium-isotope record argues for a common driver. The formation and destruction (weathering) of an oceanic LIP could account for the parallel trend in both isotope systems. The double-spike in lithium isotopes is probably related to a change in weathering congruencies. Such a chemostratigraphy is consistent with the hypothesis that an increase in silicate weathering, in conjunction with organic-carbon burial, led to drawdown of atmospheric CO 2 during the early Aptian OAE 1a.

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“…is mostly solubilized from minerals) 103 during water-rock interactions, (ii) Li is mainly derived from the chemical weathering of 104 silicate rocks (Kisakurek et al, 2005; while not involved in biological 105 processes (Lemarchand et al, 2010) and, (iii), Li isotopes are fractionated during 106 chemical weathering (Huh et al, 1998; Pistiner and Henderson, 2003) (Kisakürek et al, 2004;Lemarchand et al, 2010; Pogge von Strandmann 110 et al, 2012; Rudnick et al, 2004) or small rivers (Kisakurek et al, 2005; Kisakürek et al, 111 2004; Vigier et al, 2009; Pogge von Strandmann et al, 2010;Wimpenny et al, 2010). 112…”

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confidence: 99%

Lithium isotopes in large rivers reveal the cannibalistic nature of modern continental weathering and erosion

Dellinger

Gaillardet

Bouchez

et al. 2014

Earth and Planetary Science Letters

160

140

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Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Earth and Planetary Science Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Earth and Planetary Science Letters, 401, 1 September 2014, 10.1016/j.epsl.2014.061. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The erosion of major mountain ranges is thought to be largely cannibalistic, recycling 50 sediments that were deposited in the ocean or on the continents prior to mountain uplift. 51Despite this recognition, it has not yet been possible to quantify the amount of recycled 52 material that is presently transported by rivers to the ocean. Here, we have analyzed the 53 Li content and isotope composition (δ 7 Li) of suspended sediments sampled along river 54 depth profiles and bed sands in three of the largest Earth's river systems (Amazon, 55Mackenzie and Ganga-Brahmaputra rivers). The δ 7 Li values of river-sediments 56 transported by these rivers range from +5.3 to -3.6‰ and decrease with sediment grain 57 size. We interpret these variations as reflecting a mixture of unweathered rock fragments 58(preferentially transported at depth in the coarse fraction) and present-day weathering 59 products (preferentially transported at the surface in the finest fraction control the evolution of climate through the consumption of atmospheric carbon dioxide 83 (Berner et al., 1983;Gaillardet et al., 1999b; Raymo et al., 1988; Walker et al., 1981), 84 3 shape the Earth's surface through chemical denudation and soil production (Heismath et 85 al., 1997) and modify the composition of the continental crust (Lee et al., 2008; Liu and 86 Rudnick, 2011; Rudnick, 1995). Geochemical mass budgets of river-borne material 87 (dissolved and particulate phases) show that rivers transport both "present-day 88 weathering products" (new solid materials formed during the residence of sediment in 89 river basins by present-day water-rock interactions) and carry "inherited weathering 90 products" derived from older sedimentary rocks, which have been subject to previous 91 weathering episodes (Bouchez et al., 2011a;Gaillardet et al., 1999a). Moreover, on the 92 basis of the Nd isotope record of shales, Veizer and Jansen (1979, 1985) sugg...

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Lithium isotope systematics in a forested granitic catchment (Strengbach, Vosges Mountains, France)

Cited by 153 publications

References 49 publications

Variation of lithium isotope geochemistry during basalt weathering and secondary mineral transformations in Hawaii

Variation of lithium isotope geochemistry during basalt weathering and secondary mineral transformations in Hawaii

Lithium-isotope evidence for enhanced silicate weathering during OAE 1a (Early Aptian Selli event)

Lithium isotopes in large rivers reveal the cannibalistic nature of modern continental weathering and erosion

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