Spectroscopic isotope ratio measurement of doubly-substituted methane

Tsuji, Kiyoshi; Teshima, Hiroaki; Sasada, Hiroyuki; Yoshida, Naohiro

doi:10.1016/j.saa.2012.08.028

Cited by 16 publications

(8 citation statements)

References 12 publications

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“…New geothermometers based on the measurement of multiply substituted ('clumped') methane isotopologues (Ma et al, 2008;Tsuji et al, 2012;Stolper et al, 2014a;Stolper et al, 2014b;Ono et al, 2014a;Wang et al, in press) can constrain formation temperatures of methane. This is possible because the degree of clumped isotopic ordering, i.e., the clumped-isotope composition/distribution of a sample of methane (or any other molecule) that formed in isotopic equilibrium without further isotopic exchange after formation is a function of its formation temperature (e.g., Urey and Rittenberg, 1933;Wang et al, 2004;Eiler and Schauble, 2004;Schauble et al, 2006;Eiler, 2007;Ma et al, 2008;Yeung et al, 2012;Eiler, 2013;Eiler et al, 2014a;Stolper et al, 2014a;Stolper et al, 2014b;Webb and Miller III, 2014;Ono et al, 2014a).…”

Section: New Techniques To Identify the Source Of Methane In In The Ementioning

confidence: 99%

Distinguishing and understanding thermogenic and biogenic sources of methane using multiply substituted isotopologues

Stolper

Martini

Clog

et al. 2015

Geochimica et Cosmochimica Acta

163

240

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Please cite this article as: Stolper, D.A., Martini, A.M., Clog, M., Douglas, P.M., Shusta, S.S., Valentine, D.L., Sessions, A.L., Eiler, J.M., Distinguishing and understanding thermogenic and biogenic sources of methane using multiply substituted isotopologues, Geochimica et Cosmochimica Acta (2015), doi: http://dx. Abstract: Sources of methane to sedimentary environments are commonly identified and quantified using the stable-isotopic compositions of methane. The methane "clumped-isotope geothermometer", based on the measurement of multiply substituted methane isotopologues (13 CH 3 D and 12 CH 2 D 2), shows promise in adding new constraints to the sources and formational environments of both biogenic and thermogenic methane. However, questions remain about how this geothermometer behaves in systems with mixtures of biogenic and thermogenic gases and different biogenic environments. We have applied the methane clumped-isotope thermometer to a mixed biogenic-thermogenic system (Antrim Shale, USA) and to biogenic gas from gas seeps (Santa Barbara and Santa Monica Basin, USA), a pond on the Caltech campus, and methanogens grown in pure-culture. We demonstrate that clumped-isotope based temperatures add new quantitative constraints to the relative amounts of biogenic vs. thermogenic gases in the Antrim Shale indicating a larger proportion (~50%) of thermogenic gas in the system than previously thought. Additionally, we find that the clumped-isotope temperature of biogenic methane appears related to the environmental settings in which the gas forms. In systems where methane generation rates appear to be slow (e.g., the Antrim Shale and gas seeps), microbial methane forms in or near both internal isotopic equilibrium and hydrogen-isotope equilibrium with environmental waters. In systems where methane forms rapidly, microbial methane is neither in internal isotopic equilibrium nor hydrogen-isotope equilibrium with environmental waters. A quantitative model of microbial methanogenesis that incorporates isotopes is proposed to explain these results.

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Section: New Techniques To Identify the Source Of Methane In In The Ementioning

confidence: 99%

Distinguishing and understanding thermogenic and biogenic sources of methane using multiply substituted isotopologues

Stolper

Martini

Clog

et al. 2015

Geochimica et Cosmochimica Acta

163

240

View full text Add to dashboard Cite

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“…Spectroscopic measurements of methane clumped isotopes were first performed using a difference-frequency-generation laser (Tsuji et al, 2012), but this technique gave relatively poor precision (~20‰ (Bui et al, 2014). The sensitivity and precision of the mass spectrometric and spectroscopic methods for methane clumped isotope analyses are broadly similar.…”

Section: Measurement Techniques For Methane Clumped Isotope Analysismentioning

confidence: 99%

Methane clumped isotopes: Progress and potential for a new isotopic tracer

Douglas

Stolper

Eiler

et al. 2017

Organic Geochemistry

118

127

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Highlights:-We present a review and an expanded dataset of methane clumped isotope measurements.-Methane clumped isotope values often indicate equilibrium formation temperature.-Kinetic effects during or after methane production can affect clumped isotope values.-The wide variability in clumped isotope values suggests it will be a useful tracer. AbstractThe isotopic composition of methane is of longstanding geochemical interest, with important implications for understanding petroleum systems, atmospheric 3 greenhouse gas concentrations, the global carbon cycle, and life in extreme environments.Recent analytical developments focusing on multiply substituted isotopologues ('clumped isotopes') are opening a valuable new window into methane geochemistry.When methane forms in internal isotopic equilibrium, clumped isotopes can provide a direct record of formation temperature, making this property particularly valuable for identifying different methane origins. However, it has also become clear that in certain settings methane clumped isotope measurements record kinetic rather than equilibrium isotope effects. Here we present a substantially expanded dataset of methane clumped isotope analyses, and provide a synthesis of the current interpretive framework for this parameter. In general, clumped isotope measurements indicate plausible formation temperatures for abiotic, thermogenic, and microbial methane in many geological environments, which is encouraging for the further development of this measurement as a geothermometer, and as a tracer for the source of natural gas reservoirs and emissions.We also highlight, however, instances where clumped isotope derived temperatures are higher than expected, and discuss possible factors that could distort equilibrium formation temperature signals. In microbial methane from freshwater ecosystems, in particular, clumped isotope values appear to be controlled by kinetic effects, and may ultimately be useful to study methanogen metabolism.

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“…Tsuji et al . [] performed spectroscopic isotope measurements on 13 CH 3 D to determine the isotope ratios of 13 CH 3 D/ 12 CH 3 D and 13 CH 3 D/ 12 CH 4 in natural methane. Young et al .…”

Section: Introductionmentioning

confidence: 99%

A model for ¹²CH₂D₂ and ¹³CH₃D as complementary tracers for the budget of atmospheric CH₄

Haghnegahdar

Schauble

Young

2017

Global Biogeochemical Cycles

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We present a theoretical model to investigate the potential of 13CH3D and 12CH2D2, the doubly substituted mass‐18 isotopologues of methane, as tools for tracking atmospheric methane sources and sinks. We use electronic structure methods to estimate kinetic isotope fractionations associated with the major sink reactions of methane in air (reactions with OH and Cl radicals) and combine literature data with reconnaissance measurements of the relative abundances of 13CH3D and 12CH2D2 to estimate the compositions of the largest atmospheric sources. This model atmospheric budget is investigated with a simplified box model in which we explore both steady state and dynamical (nonsteady state) conditions triggered by changes in emission or sink fluxes. The steady state model predicts that sink reactions will generate a marked (>100‰) clumped isotope excess in atmospheric Δ12CH2D2 relative to the net source composition. 12CH2D2 measurements may thus be useful for tracing both atmospheric source and sink fluxes. The effect of sinks on Δ13CH3D is much less pronounced, indicating that 13CH3D in air will give a more focused picture of the source composition.

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Spectroscopic isotope ratio measurement of doubly-substituted methane

Cited by 16 publications

References 12 publications

Distinguishing and understanding thermogenic and biogenic sources of methane using multiply substituted isotopologues

Distinguishing and understanding thermogenic and biogenic sources of methane using multiply substituted isotopologues

Methane clumped isotopes: Progress and potential for a new isotopic tracer

A model for ¹²CH₂D₂ and ¹³CH₃D as complementary tracers for the budget of atmospheric CH₄

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Spectroscopic isotope ratio measurement of doubly-substituted methane

Cited by 16 publications

References 12 publications

Distinguishing and understanding thermogenic and biogenic sources of methane using multiply substituted isotopologues

Distinguishing and understanding thermogenic and biogenic sources of methane using multiply substituted isotopologues

Methane clumped isotopes: Progress and potential for a new isotopic tracer

A model for 12CH2D2 and 13CH3D as complementary tracers for the budget of atmospheric CH4

Contact Info

Product

Resources

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A model for ¹²CH₂D₂ and ¹³CH₃D as complementary tracers for the budget of atmospheric CH₄