Application of methane clumped isotope approach in natural abiotic methane reservoirs

为了更好地限制天然碳氢化合物气体的来源，我们在日本群岛不同类型的泥火山中应用了新的分析技术，即甲烷块同位素方法。我们在(1)Tokamachi地区(Gamo，Murono和Kusozu)和(2)Goshogake地区进行了多次实地考察，收集了泥火山和(或)地表渗漏排放的气体。通过甲烷块状同位素分析和其他地球化学方法，如整体碳同位素组成和烷烃和二氧化碳浓度，丙烷的位置特定同位素分析，我们成功地限制了托卡马奇型泥火山微生物活动(生物降解过程)的贡献。这些进展已经在EGU2023会议上发表，并将很快提交给一家国际期刊。来年，我们将主要关注其在Goshogake型泥火山中的应用，其中碳氢化合物被认为是来自非生物来源的。

To better constrain the origins of natural hydrocarbon gases, we have applied the novel analytical technique, i.e., methane clumped isotope approach, in different types of mud volcanos across the Japanese archipelago. We have conducted multiple field trips to collected emitted gases from mud volcanos and/or surface seeps in (1) Tokamachi area (Gamo, Murono and Kusozu), and (2) Goshogake area.By combination of methane clumped isotope analysis and other geochemical approaches, such as bulk carbon isotope compositions and concentrations of alkanes and CO2, position specific isotope analysis of propane, we have successfully constrained the contribution of microbial activity (biodegradation process) in Tokamachi-type mud volcanos. The progresses have been presented at EGU2023 conference and will be submitted to an international journal soon.In the coming year, we will mainly focus on its application in Goshogake-type mud volcanos, in which hydrocarbons have been assumed as considerately contributed from abiotic source.