Tamagawa hyper-acidic hot spring and phreatic eruptions at Mt. Akita-Yakeyama: Part 1. The isotopic and chemical characteristics of the hot spring water

摘要

Isotopic (D, H-3, O-18, and S-34) and chemical studies on the hyper-acidic hot spring waters (Obuki: pH 1.1), other hot spring waters, and fumarolic gases taken in 1990-1992 at Tamagawa Hot Spring, Akita, Japan were undertaken to investigate the source and behavior of sulfur compounds. The Obuki hot spring water discharges after mixing of magmatic gas with meteoric water and underground vapor-liquid separation. SO42- and H2S was formed by the disproportionation reaction of SO2 at around 220 degrees C. Tritium concentration indicated that the subsurface residence time of the Obuki hot spring water is 13-25 years. In the downstream of the Obuki hot spring, there are many hyper-acidic hot springs that are diluted by meteoric water and flow as a river (Yukawa). (C) 2021 Elsevier B.V. All rights reserved.