Figure 5From: Real-time drilling mud gas monitoring for qualitative evaluation of hydrocarbon gas composition during deep sea drilling in the Nankai Trough Kumano BasinResults for deuterium and methane carbon isotope ratios. Left panel: δDCH4 values determined for different gas samples from IODP Expedition 338 [23]. Horizontal bars indicate the standard deviation of duplicate measurements. Right panel: δ13CCH4 data obtained during drilling borehole C0002F (modified from [23]). Starting at 1700 mbsf, the δ13CCH4 data indicate a shift to methane of thermogenic origin (boundaries after [26]).Back to article page