Isotope compositions in a natural gas seep, French Alps

The Fontaine Ardente (FA) and Rochasson (ROC) natural gas seepage sites are located southwest (FA) and east (ROC) of Grenoble, France. For both field sites, gas is thought to originate from buried Middle Jurassic mudstones and argillaceous limestones and thought to migrate upward along small faults. At FA, the site located along a small seepage close to the river bed of a small creek. The gas seepage site at ROC is located along the flank of a thalweg and is linked to a small landslide in clayey horizons. New methane clumped isotope data is correlated to previously published data by Gal et al (2017) and recent isotopic data acquired within SECURe deliverable 3.4. During October 2019, 5 samples were collected from the FA and ROC sites and the following analyses were conducted: - Gas composition (C1-C5, CO2, N2, H2S, Ar) and and stable isotope analyses (methane δ13C and δD, CO2 δ13C, δ15N) - Methane clumped isotope analyses (Δ13CD and ΔDD) The dataset was created within SECURe project (Subsurface Evaluation of CCS and Unconventional Risks) - https://www.securegeoenergy.eu/. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 764531Fontaine Ardente（FA）与Rochasson（ROC）天然气渗漏点位分别坐落于法国格勒诺布尔的西南侧（FA点位）与东侧（ROC点位）。两处点位的天然气均被认为源自埋藏的中侏罗统泥岩与泥质灰岩，并沿小型断层向上运移。其中FA点位沿一处小型渗漏带分布，毗邻一条小型溪流的河床；ROC点位的天然气渗漏带位于溪谷谷底线的坡岸，与黏土层位中的小型滑坡相关联。 本次新增的甲烷团簇同位素（methane clumped isotope）数据，已与Gal等人2017年发表的既往数据，以及SECURe项目交付成果3.4中获取的最新同位素数据完成关联。2019年10月期间，研究人员从FA与ROC点位共采集5份样品，并开展了如下分析： - 气体组分（C1-C5、CO₂、N₂、H₂S、Ar）测定与稳定同位素分析（甲烷δ¹³C、δD，CO₂δ¹³C、δ¹⁵N） - 甲烷团簇同位素分析（Δ¹³CD与ΔDD） 本数据集依托SECURe项目（Subsurface Evaluation of CCS and Unconventional Risks，即CCS与非常规风险地下评估）构建，项目官网为https://www.securegeoenergy.eu/。该项目获得欧盟地平线2020研究与创新计划资助，资助协议编号为764531。