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The authors obtained 30 core samples from 15 wells in Gangxi fault belt, Huanghua Depression. Using a VG5400 mass spectrometer, the helium isotopic compositions in fluid inclusion of these samples were analysed. Interpreta- tion of results suggests a significant amount of man- tle-derived helium in the inclusions, which were likely trapped during Neocene. Mantle-derived helium have mostly accumulated in the intersections of the NWW trending Xuz- huangzi and NE trending Gangxi faults, and decreased away from the intersections. This pattern implied a close relation- ship to the local tectonic setting. Gangxi fault belt experi- enced intensive neo-tectonic activities in the Cenozoic. Widespread faulted-depressions and strong volcanic erup- tions manifested its tectonic status of extensional stress field. Mantle uplift caused the movement of magma that carried mantle-derived gas, and the deep-rooted tension faults pro- vided the passages for the gases to shallow crust levels. High-content abiogenic CO2 pools occurred in the study area, hence, using the helium isotopic compositions is of great sig- nificance to the exploration of abiogenic natural gases.
The authors obtained 30 core samples from 15 wells in Gangxi fault belt, Huanghua Depression. Using a VG5400 mass spectrometer, the helium isotopic compositions in fluid inclusion of these samples were analyzed. Interpretation of results suggests a significant amount of man- tle- derived helium in the inclusions, which were likely trapped during Neocene. Mantle-derived helium have a more accumulated in the intersections of the NWW trending Xuz- huangzi and NE trending Gangxi faults, and decreased away from the intersections. This pattern implied a close relation- ship to the local tectonic setting. Gangxi fault belt experi- enced intensive neo-tectonic activities in the Cenozoic. Widespread faulted-depressions and strong volcanic erup- tions manifested its tectonic status of extensional stress field. Mantle uplift caused the movement of magma that animal mantle-derived gas, and the deep-rooted tension faults pro- vided the passages for the gases to shallow crust levels. High-content abiogenic gas pools have occurred in the study area, hence, using the helium isotopic compositions is of great sig- nificance to the exploration of abiogenic natural gases.