Distribution of methane and carbon dioxide concentrations in the near-surface zone over regional fault zones and their genetic characterization in the Pszczyna-Oświęcim area (SE part of the Upper Silesian Coal Basin, Poland)

摘要: Abstract The objective of this paper was to characterize the variability methane (CH4) and carbon dioxide (CO2) concentrations in near-surface zone, measured along 4 selected sampling lines positioned perpendicularly regional fault zones, SE part Upper Silesian Coal Basin (USCB), Poland. This way it possible check migration activity these gases surface through low-permeable Miocene strata. It also evaluate applicability geochemical survey methodology identification potential accumulations free natural gas topmost parts Carboniferous formations USCB. results 319 soil-gas samples were supported by stable isotope analyses related geological setting distribution at various depths. Moreover, included area closed remediated Andrzej VII mining shaft, where 5 taken. Additionally, flux evaluated 3 measurement points which increased detected. maximum CH4 CO2 soil 15.4 9.39 vol%, respectively. Soil contain both thermogenic microbial that migrated from secondary primary zones within Pennsylvanian coal-bearing In some sites, generated oxidation organic matter and/or a zone. Anomalous generally found over elevated fragments erosional structures formations. indicates presence beneath overburden. However, anomalies did not always correlate with accumulations. correlated cut traps saturated upper Relatively low values observed for emissions (maximum: 25 4320 mg m−2 d−1, respectively). suggests relatively dynamics depth