Abstract A geochemical survey was carried out (May 2016) in the Rincon de Parangueo maar in Valle de Santiago, Mexico. The challenge was to measure CO2 and CH4 fluxes discharged from soil and to investigate the chemical and isotopic compositions of interstitial soil gases and remaining vents at the bottom of maars system subjected to critical and high rate drawdown aquifer. Total CO2 flux calculated by sequential Gaussian simulation is 10.6 ton d−1 (±2.1 ton d−1) over the entire crater maar area. Two degassing groups were recognized: Group A (background degassing) with values lower than 10 g m−2 d−1 (40% of the total measurements) and Group B with values ranging between 10 and 347.1 g m−2 d−1 (60% of the total amount of measurements). CH4 flux ranges from 2.1 to 1577 g m−2 d−1. CH4/CO2 flux mean ratio is ~20.51 while CH4/CO2 concentration ratios are 78 and 119 for bubbling gases and 8.4 for interstitial gases. The δ13C-CH4 values are ~65 per mil vs V-PDB indicating a biogenic origin of methane in bubbling and interstitial gases. The δ13C-CO2 values, ranging from −10.6 to −27.6 and −1.9 per mil vs V-PDB for bubbling gases and the interstitial gases, respectively, suggest secondary CO2 consumption within the soil.

中文翻译：

---

从 Rincón de Parangueo Maar（墨西哥）排放的 CO2 总产量和碳来源

摘要 2016 年 5 月在墨西哥 Valle de Santiago 的 Rincon de Parangueo maar 进行了地球化学调查。面临的挑战是测量从土壤中排放的 CO2 和 CH4 通量，并研究受临界和高速下降含水层影响的马尔斯系统底部的间隙土壤气体和剩余喷口的化学和同位素组成。在整个火山口玛尔区域，通过连续高斯模拟计算的总 CO2 通量为 10.6 吨 d-1 (±2.1 吨 d-1)。识别出两个脱气组：A 组（背景脱气）的值低于 10 gm-2 d-1（总测量值的 40%）和 B 组的值范围在 10 到 347.1 gm-2 d-1（60%的测量总量）。CH4 通量范围从 2.1 到 1577 g m-2 d-1。CH4/CO2 通量平均比率为~20。51 而 CH4/CO2 浓度比对于起泡气体为 78 和 119，对于间隙气体为 8.4。δ13​​C-CH4 值与 V-PDB 相比为 ~65 per mil，表明气泡和间隙气体中甲烷的生物起源。δ13​​C-CO2 值范围分别为 -10.6 至 -27.6 和 -1.9/mil 与 V-PDB 的气泡气体和间隙气体相比，表明土壤中的二次 CO2 消耗。