岡山大学 地球科学研究報告
Published by Okayama University Earth Science Reports Editorial Committee

Hydrogen and oxygen isotope ratios of thermal waters of Okayama Prefecture, Japan

Yamamoto Masahiro
Ichimoto Hideo
Komatsu Shinji
Yamashita Ruka
Abstract
Hydrogen and oxygen isotope rations of thermal waters from 46 spas in Okayama Prefecture range from -62.6 to -29.2% in δD and from -10.0 to -4.4% in δ18O, respectively. The isotope rations indicate that all but one of the thermal water in Okayama prefecture are meteoric in origin. The Ofuku thermal water is the only exception, which is probably a mixture of seawater and meteoric water with the ratio of about 1. Sulfur isotope rations of dissolvel sulfate in the thermal waters range from -6.2 ti 59.3% in δ34S. The high δ34S values observed in some thermal waters may be due to bacterial reduction of sulfate.
Keywords
Hydrogen isotope ratio
Oxygen isotope ratio
Sulfur isotope ratio
Thermal water
Spa Okayama
ISSN
1340-7414
NCID
AN10506284