| 研究課題/領域番号 |
15K17774
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| 研究機関 | 東京工業大学 |
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研究代表者 |
ジルベルト アレキシー 東京工業大学, 地球生命研究所, 助教 (20726955)
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| 研究期間 (年度) |
2015-04-01 – 2017-03-31
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| キーワード | アイソトプ |
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| 研究実績の概要 |
We developed and implemented a new system enabling the analysis of 13C/12C content for each carbon atom of propane and butanes (namely “intramolecular isotope composition”).
The apparatus has been used to analyse samples synthesized in the lab, simulating propane formation through abiotic (radical polymerization of CH4) and thermogenic (thermal degradation of organic matter) processes.
The results show that the intramolecular isotope composition of propane are different from the 2 different processes: while abiotic samples show a relatively homogeneous 13C distribution, thermogenic samples show a strong 13C depletion on the terminal C-atom position, consistent with models existing.
Moreover, the signature of synthesized abiotic samples fits perfectly that from abiotic sample from hydrothermal system Hakuba-Happo (Japan) reemphasizing the role of hydrothermal systems in abiotic production.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Our progress so far fits perfectly the original objectives: developing the apparatus and starting the analysis of amples from different origins.
The apparatus now works very well and is able to determine intramolecular isotope composition of propane and butanes in one single injection, with high sensitivity and high precision (Gilbert et al. 2016, GCA).
We also started the analysis of samples from field (Hakuba-Happo, Japan; Apulian basin, Italy). Some of them will require more purification steps than expected but should be analyzed soon. We are a bit in advance regarding simulating processes reated to natural gas formation/consumption. We already started thermal degradation of organic matter as a proxy for thermogenic gas.
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| 今後の研究の推進方策 |
We shall work on improving the purification steps for some specific natural gas samples, especially those contiaing high amount of carbon dioxide or methane.
We will develop a model based on kinetics and isotope fractionation factors to explain the data otined so far on abiotic samples,m both at the molecular and at the intramoledcular level.
An important step for this project will be to determine the fractionation factors for simulated sinks and sources of natural gas. We already started experiments to simulate abiotic formation. We will make culture experiments aiming at evaluating fractionation factors associated with propane degradation by microorganisms, both un der the presence and in the absence of oxygen.
The above-mentionned steps will help refining the determinants of intramolecular isotope composition of natural gas hydrocarbons, and our understanding ofthe sources and sinks of natural gas on Earth.
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| 次年度使用額が生じた理由 |
I postponed to buy chemicals to conduct an experiment.
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| 次年度使用額の使用計画 |
So I will do so this year FY2016.
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