Extended Data Fig. 1: Relationship between noble gas isotopic ratios in the Olla (blue circles) and Nebo-Hemphill (orange triangles) oil fields.
From: Rapid microbial methanogenesis during CO2 storage in hydrocarbon reservoirs
Both fields show a resolvable mantle component that is significantly greater in the Olla Oil Field. One standard deviation error bars are within symbol size. a, He isotopic ratios versus 4He/20Ne ratio. Air-corrected He isotopes are reported relative to air (RA = 1.38 × 10−6 (ref. 69)). All samples are in excess of typical radiogenic production (0.02RA), requiring a mantle contribution. High 4He/20Ne indicates negligible air contamination in the samples. b, Three neon isotope plot. The crustal production line68 reflects the observed trend in typical crustal fluids. The mantle-air line represents mixing between air and a MORB-like endmember67. Data are consistent with mixing between air and a mantle-rich component. In both He and Ne isotopes, the mantle signal is stronger in the Olla Oil Field.
