Gas and water samples were collected from coalbed methane (CBM) wells, rivers, and springs in the southern Junggar Basin (SJB). These samples were analyzed for gas composition, stable isotopes, 16s ribosomal ribonucleic acid sequence, chemical compositions, and radioisotopes. The objective of this study was to understand CBM genesis in the Junggar Basin, the reason for abnormal CO2 accumulation, the development of microbial communities, the source of coalbed water, and the timing of methanogenesis. The CBM genesis is complex in the SJB, but it is closely related to microbial activities. The stagnant zone, which experiences limited groundwater recharge, may represent a relatively closed system where CO2 is easily trapped and the residual CO2 becomes progressively enriched in 13C. Only two families of methanogens (i.e., Methanobacteriaceae and Methanospirillaceae) are present in the coalbed waters, indicating that CO2 reduction is the main pathway for generating microbial gas. The coalbed water samples from the Houxia and Manasi–Hutubi regions plot around the local meteoric water line (LMWL), indicating recharge by modern meteoric water and rivers. However, the samples from the Miquan and Fukang regions plot below the LMWL, reflecting older snowmelt water recharge. Isotopic dating indicates that the age of coalbed water in the Miquan and Fukang regions is 43.5–2000 ka. Early coalification and later hydrological events collectively determined the regional variations in CBM genesis and gas composition in the SJB.

中文翻译：

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准gar尔盆地南部气水特征及其对煤层气成藏模式的启示

天然气和水样本是从准Jung尔盆地南部（SJB）的煤层气（CBM）井，河流和泉水中采集的。分析了这些样品的气体组成，稳定同位素，16s核糖体核糖核酸序列，化学组成和放射性同位素。这项研究的目的是了解准gar尔盆地的煤层气成因，异常CO2积累的原因，微生物群落的发展，煤层水的来源以及甲烷化的时间。SJB中的煤层气成因很复杂，但它与微生物活动密切相关。停滞区域的地下水补给有限，这可能代表一个相对封闭的系统，在该系统中，二氧化碳很容易被捕集，剩余的二氧化碳逐渐在13C中富集。只有两个家族的产甲烷菌（即，煤层水中存在甲烷细菌科和甲烷螺旋藻科），这表明二氧​​化碳的减少是产生微生物气体的主要途径。来自后峡和玛纳斯-胡图比地区的煤层水样点分布在当地的流水线（LMWL）周围，表明现代的流水和河流补充了水。但是，来自米泉和富康地区的样本位于LMWL下方，反映了较旧的融雪水补给。同位素测年表明，米泉和阜康地区的煤层水年龄为43.5–2000 ka。早期的煤化作用和后期的水文事件共同决定了SJB中煤层气成因和天然气成分的区域差异。来自后峡和玛纳斯–胡图比地区的煤层水样点分布在当地的流水线（LMWL）周围，表明现代的流水和河流补充了水。但是，来自米泉和富康地区的样本位于LMWL下方，反映了较旧的融雪水补给。同位素测年表明，米泉和阜康地区的煤层水年龄为43.5–2000 ka。早期的煤化作用和后期的水文事件共同决定了SJB中煤层气成因和天然气成分的区域差异。来自后峡和玛纳斯–胡图比地区的煤层水样点分布在当地的流水线（LMWL）周围，表明现代的流水和河流补充了水。但是，来自米泉和富康地区的样本位于LMWL下方，反映了较旧的融雪水补给。同位素测年表明，米泉和阜康地区的煤层水年龄为43.5–2000 ka。早期的煤化作用和后期的水文事件共同决定了SJB中煤层气成因和天然气成分的区域差异。同位素测年表明，米泉和阜康地区的煤层水年龄为43.5–2000 ka。早期的煤化作用和后期的水文事件共同决定了SJB中煤层气成因和天然气成分的区域差异。同位素测年表明，米泉和阜康地区的煤层水年龄为43.5–2000 ka。早期的煤化作用和后期的水文事件共同决定了SJB中煤层气成因和天然气成分的区域差异。