At present a total of 118 hot springs are distributed throughout Thailand. Several studies with a
focus on high-temperature hot springs related to geothermal resources were conducted in the
northern and southern parts of the country. Geochemical data, however; especially isotopes of
medium-to-low temperature hot springs are still scarce. Geochemical water analyses and isotope
studies can provide crucial information for the future economical development of the hot springs,
such as reservoir temperature, water source and quality. This study aims to investigate the chemical
composition and stable isotopes (δ18O, δD) of three hot spring waters from western Thailand; Hin
Dad, Bor Klueng and Ban Samorthong (surface water temperatures of 40-50 °C). The chemical
type of the hot spring waters from Ban Samorthong and Bor Klueng are alkaline-carbonate, while
Hin Dad hot spring is a calcium-carbonate type with high amount of sulfate, which is related to
bedrock. Based on the silica geothermometer, reservoir temperatures are 65-90 °C. The stable
isotopes δ18O and δD of all hot spring waters suggest a recharge with meteoric waters.
Keywords
Water chemistry; Medium-low temperature hot springs; Western Thailand; ?18O and ?D isotopes