Lithium isotopic composition and concentration of the upper continental crust

Teng, Fang‐Zhen; McDonough, William F.; Rudnick, Roberta L.; Dalpé, Claude; Tomascak, Paul B.; Chappell, B. W.; Gao, Shan

doi:10.1016/j.gca.2004.03.031

Cited by 404 publications

(339 citation statements)

References 66 publications

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“…The isotopic ratio of Li in modern oceans is ~31‰ (Tomascak et al, 1999). The continental crust has an average lithium-isotope composition of 0 ± 3‰ (Teng et al, 2004), whereas mid-ocean-ridge basalts usually have isotopic values of 3-5‰ (Elliott et al, 2006;Tomascak et al, 2008Tomascak et al, , 1999. The difference of the isotopic ratio between the ocean water and continental and marine silicates is a function of high-and low-temperature alteration of these minerals.…”

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

confidence: 99%

“…The chosen isotope systems are controlled by different factors. Li isotopes can be used as a proxy for silicate-weathering congruency, although weathering of basaltic (oceanic) or granitic (continental) crust cannot be differentiated due to their similar isotopic values (Teng et al, 2004). Ca isotopes may hold information about weathering of both continental crust and carbonates (Blättler et al, 2011).…”

Section: Constraints From Multi-isotope Excursionsmentioning

confidence: 99%

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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

105

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

confidence: 99%

Section: Constraints From Multi-isotope Excursionsmentioning

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

105

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“…After purification of Li on a cation exchange resin (Bio-Rad AG50w-X12), Li isotopic measurements were carried out using a Nu Plasma MC-ICP-MS at the University of Maryland. Details of the instrumental analysis are given by Teng et al (2004). Each sample analysis is bracketed by measurements of the L-SVEC standard and the δ 7 Li value of the sample is calculated relative to the average of the two bracketing L-SVEC runs.…”

Section: Lithium Isotopic Analysesmentioning

confidence: 99%

“…Basalt BHVO-1 gave δ 7 Li = 4.6 ± 1.0 ‰ (2σ, n=4) and muscovite-quartz schist SDC-1 gave δ 7 Li = 2.0 ± 0.9 ‰ (2σ, n=6 with two different dissolutions). The external precision of Li isotopic analyses, based on 2σ of repeat runs of pure Li standard solutions and rock solutions over a four-year period, is ≤ ± 1.0 ‰ (Teng et al, 2004(Teng et al, , 2007.…”

Section: Lithium Isotopic Analysesmentioning

confidence: 99%

A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

et al. 2011

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Two distinct types of eclogites from the Raspas Complex (Ecuador), which can be distinguished based on petrography and trace element geochemistry, were analyzed for their stable (Li, O) and radiogenic (Sr, Nd) isotope signature to constrain metasomatic changes due to fluid-overprinting in metabasaltic rocks at high-pressure conditions and to identify fluid sources. MORB-type eclogites are characterized by a relative LREE depletion similar to MORB. High-pressure (HP) minerals from this type of eclogite have highly variable oxygen isotope compositions (garnet: +4.1 to +9.

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“…However, in the context of water/rock 61 interactions, numerous studies (Huh et al, 1998(Huh et al, , 2001Pistiner et al, 2003; Kisakurek et al, 62 2004 Kisakurek et al, 62 , 2005 Pogge von Strandmann et al, 2006;Millot et al, 2007Millot et al, , 2010aMillot et al, , 2010b have 63 clearly shown that isotopic fractionation supports the enrichment of the heavy isotope ( 7 Li) in 64 solution, the light isotope ( 6 Li) being preferentially retained in secondary weathering 65 minerals. Silicate rocks display Li isotope compositions ranging from -2 to +10‰ (Coplen et 66 al., 2002;Teng et al 2004), that of seawater is ~ +31‰ (Millot et al, 2004), river water has 67 intermediate isotopic compositions (+6 to +23‰, Huh et al, 1998), and saline (thermo-68 mineral) water generally has isotopic compositions in the range of 0 to +15‰ 69 Négrel, 2007, Millot et al, 2010b) although Falkner et al (1997) found Li isotopic 70 compositions in the range of +17 to +35‰ in hot spring water from Lake Baikal. 71…”

Section: -Introductionmentioning

confidence: 99%

Lithium isotopes as tracers of groundwater circulation in a peat land

et al. 2010

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8 9Water circulation in the peat bog of a maar depression in the Massif Central (France) was traced with 10 lithium isotopes on water samples collected in the area from springs, surface-and groundwaters, as 11 well as on solid samples taken from peat bogs. 18In the present study, we explain the extremely enriched 7 Li signature of the groundwaters by an -IntroductionA wetland is an area covered at least part-time by usually quite shallow water. Wetlands can 36 be natural or artificial, permanent or temporary, and the water in them can be static or 37 flowing, and fresh, brackish or salty. Wetlands form where water collects in a low-lying area 38 with poor drainage. The water filling a wetland can have many origins: precipitation is a 39 major source of water for many wetlands, but others are maintained by water that periodically 40 overflows from rivers, lakes, etc., whereas a third source of water for wetlands is 41 groundwater. All three sources generally deliver water to wetlands in regular cycles, based on 42 the natural cycle of water through the hydrosphere. It is also worth noting that understanding 43 the hydrology of a wetland is primordial for efficient flood control, paleoclimate analyses, 44 and studying its role in the overall ecology. 45The present study investigates the use of Li and its isotopes as a proxy of ground-to-surface 46 water exchanges in a peatland from a mire-lake complex in the French Massif Central, as the 47 capability of Li isotopes as hydrogeological tracers was earlier demonstrated by Hogan and 48 Blum (2003). As one aim of the work was to determine geochemical constraints on the 49 hydrological functioning of a peatland, our primary objective was to constrain hydro-reservoir 50 signatures and the exchanges of water and solutes with adjacent ground and uplands. One 51 particularly important aspect of this work was to evaluate the mechanisms of water and solute 52 transfer between the reservoirs by applying Li as a new isotopic tracer. 53Lithium has two stable isotopes of mass 6 and 7, with natural abundances of 7.5% and 92.5% 54 respectively. Lithium is a mobile element that tends preferentially to go into the fluid phase 55 during water/rock interactions. The relative mass difference between the two isotopes is 56 considerable at 17%, generating significant mass-dependant fractionation during geochemical 57 processes. The range of variation in lithium-isotope compositions is more than 50‰ in 58 geological materials (see Coplen et al., 2002;Tomascak, 2004 for data compilation). As Li is 59 3 a recently developed isotopic tracer, not all the processes that could induce and control 60 isotopic fractionation are as yet well constrained. However, in the context of water/rock 61 interactions, numerous studies (Huh et al., 1998(Huh et al., , 2001Pistiner et al., 2003; Kisakurek et al., 62 2004 Kisakurek et al., 62 , 2005 Pogge von Strandmann et al., 2006;Millot et al., 2007Millot et al., , 2010aMillot et al., , 2010b have 63 clearly shown that isotopic fractionation ...

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Lithium isotopic composition and concentration of the upper continental crust

Cited by 404 publications

References 66 publications

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

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

A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

Lithium isotopes as tracers of groundwater circulation in a peat land

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