Geochemical features and the flow system for saline mineral spring at the Tsuwano Town, Shimane Prefecture

Abstract

This study examined the geochemical properties and the distribution of mineral spring water, river water and associated discharge gases in Tsuwano Town, Shimane Prefecture, Western Japan. In Tsuwano, high Na-Cl groundwater emits gas bubbles composed mainly of CO₂. The geochemical properties of mineral spring water, gas, hydrogen and oxygen isotopes and noble gas isotopes suggest that mineral spring water at Tsuwano possibly contains deep-seated fluid. In addition, the largest deep-seated fluid flux occurs along active faults, suggesting that active faults are pathways for fluid upwelling from depth. Furthermore, in Tsuwano, deep-seated fluid discharge occurs along the Lake Ohara-West Yauneyama fault system and surface fractures.