Oxygen and hydrogen isotopes in deep thermal waters from the south meager creek geothermal area, british columbia, canada

• Published in: Geothermics Vol. 22; no. 2; pp. 79 - 89
• Main Authors: Ghomshei, Morteza M., Clark, Ian D.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.1993; Elsevier Science
• Subjects: 150200 - Geology & Hydrology of Geothermal Systems; 152004 - Geothermal Data & Theory- Isotope & Trace Element Studies; BRITISH COLUMBIA; CANADA; CHEMISTRY; DATA; DEUTERIUM; DEVELOPED COUNTRIES; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; EVEN-EVEN NUCLEI; Exact sciences and technology; EXPERIMENTAL DATA; FLUIDS; GEOCHEMISTRY; GEOLOGIC FRACTURES; GEOLOGIC STRUCTURES; GEOTHERMAL ENERGY; GEOTHERMAL FLUIDS; GEOTHERMAL RESOURCES; GEOTHERMAL WELLS; Geothermics; GROUND WATER; HOT SPRINGS; HYDROGEN COMPOUNDS; HYDROGEN ISOTOPES; INFORMATION; ISOTOPE RATIO; ISOTOPES; LIGHT NUCLEI; METEORIC WATER; Mineralogy; NORTH AMERICA; NUCLEI; NUMERICAL DATA; ODD-ODD NUCLEI; ORIGIN; OXYGEN 18; OXYGEN COMPOUNDS; OXYGEN ISOTOPES; PERMEABILITY; RECHARGE; RESOURCES; Silicates; STABLE ISOTOPES; TEMPERATURE MEASUREMENT; THERMAL SPRINGS; WATER; Water geochemistry; WATER SPRINGS; WELLS; North America; Western Canada; British Columbia; stable isotopes; O-18; water wells; permeability; ground water; rain water; infiltration; dilution; hydrochemistry; recharge; geothermal reservoirs; water vapor; pH; cooling; hot springs; temperature; thermal waters; D/H; fractures
• ISSN: 0375-6505; 1879-3576
• DOI: 10.1016/0375-6505(93)90048-R

Deuterium and oxygen-18 ( 18O) have been measured in deep thermal, shallow thermal and non-thermal water samples collected at various times between 1982 and 1989 from the Meager Creek area, with the aim of assessing the origin of the thermal waters. The isotopic composition of the reservoir waters ( δ 18 O = −13‰ and δ D = −114.8‰ ) was calculated from data on post-flash deep thermal waters, using a two-stage steam loss model. The reservoir composition shows an oxygen shift of 2.4‰ relative to the local meteoric water line. The composition of the recharge, obtained by removing the oxygen shift, is isotopically heavier than the average local meteoric waters, suggesting that the recharge may be from an area to the west of Mt Meager where isotopically heavier ground-waters are likely to be found. The small δ 18O shift of the deep high-temperature waters is indicative of dominance of fracture-related permeability in the reservoir. Analysis of the chemistry and the temperature of the waters from hot springs and shallow thermal wells suggests that these waters have evolved from the deep geothermal waters through dilution by meteoric waters and about 40°C adiabatic cooling (steam loss).