[SGC40-P08] Helium isotopes in Tachibana Bay and Shimabara Bay, Nagasaki
Keywords:Helium Isotopes, Hydrothermal vents, Tachibana Bay
The surrounding bays around Shimabara Peninsula in Nagasaki were recently studied for the existence of hydrothermal springs and vents. Physico-chemical properties characteristic of hydrothermal activity were detected on the seafloor. For this study, we use helium isotopes to detect the occurrence of hydrothermal springs on the seafloor in both Tachibana Bay and Shimabara Bay. Samples were collected using a CTD-CMS system and analyzed using a Noble Gas Mass Spectrometer. Our data supplements the discovery of hydrothermal venting along known faults on the seafloor. We present the results of noble gas measurements conducted on water samples and discuss the relationship between our observations and the tectonic setup of the surrounding region.