Bacterial production of methane and its influence on ground-water chemistry in east-central Texas aquifers

Geochemical and isotopic data for methane and ground water indicate that gaseous hydrocarbons in Eocene aquifers in east-central Texas form by bacterial processes. The 13 C values of methane from five wells in the clay-rich Yegua and Cook Mountain Formations range from -71 to -62. Methane from ten wells in the cleaner sands of the Sparta and Queen City Formations have 13 C values between -57 and -53. The carbon isotopic difference between methanes from the Yegua and Sparta aquifers is comparable to the isotopic difference in sedimentary organic matter from outcrops of the units, suggesting substrate control on the 13 C of bacterial methane. Hydrogen isotopic compositions of methane from the aquifers are similar, averaging -181. This high value suggests methane production predominantly by CO 2 reduction. -from Authors

Bacterial production of methane and its influence on ground-water chemistry in east-central Texas aquifers Academic Article