Neogene and Quaternary dikes and related joints as conduits for recent juvenile degassing: case studies from the seismically active region of NW-Bohemia, Czech Republic

Abstract The contemporary occurrence of juvenile gas emissions at springs or mofettes in active volcanic areas can be observed worldwide. This correlation is less frequent with dormant post-volcanic activity. NW-Bohemia/Vogtland region located the Eger rift zone (Czech Republic) provides an intriguing example this between numerous Neogene-aged post-volcanism locations and fluid emission sites. Newly discovered dikes diatremes are close to vents highest helium isotope ratios ( 3 He/ 4 He) about 6 R a . Our results lend support hypothesis that feeder their fractured wall rocks should considered predominant conduits for continuous upwelling fluids. Moreover, 77% CO 2 sites diatremes, i.e., within distance km. studies reveal spatial dependence values spring estimated distances basaltic bodies. confirm negative trend known from literature. That is, decrease increasing dikes.