Isotopic evidence for a magmatic contribution to fluids of the geothermal systems of Larderello, Italy, and the Geysers, California

Journal Article · Tue Feb 01 00:00:00 EST 1994 · Geothermics (International Journal of Geothermal Research and its Applications); (United States)

DOI:https://doi.org/10.1016/0375-6505(94)90043-4· OSTI ID:7115455

D'Amore, F; Bolognesi, L ^[1]

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1. International Inst. for Geothermal Research, Pisa (Italy). Italian National Research Council

The isotopic composition of steam from the Larderello, Italy, and The Geysers, California, geothermal fields is used to determine the source(s) of the fluid in these two vapor-dominated systems. Previous interpretations suggested the isotopic composition of the two systems was mainly the result of reactions at high temperature between deeply circulating meteoric water and largely sedimentary host rocks. The authors interpret the data for the Larderello and The Geysers fluids as indicating that meteoric water, exchanged with host rocks, mixes with local magnetic water. The isotopic composition of end-member magmatic water at The Geysers is typical of convergent plate boundaries ([delta][sup 18]O = +5 to +11 per mil; [delta]D = [minus]10 to [minus]35 per mil); a local isotopic composition of +11 to +15 per mil [delta][sup 18]O and [minus]15 to [minus]35 per mil [delta]D is suggested for the Larderello magmatic water. The magmatic water derived from the crystallization of underlying magma. Metamorphic waters, derived from dehydration reactions of OH-bearing minerals, may also make a minor contribution to the geothermal fluids.

• OSTI ID: 7115455
• Journal Information: Geothermics (International Journal of Geothermal Research and its Applications); (United States), Vol. 23:1; ISSN 0375-6505
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
CALIFORNIA
VAPOR-DOMINATED SYSTEMS
ITALY
MAGMATIC WATER
CHEMICAL COMPOSITION
ISOTOPE RATIO
ORIGIN
GEOCHEMISTRY
STEAM
CHEMISTRY
DEVELOPED COUNTRIES
ENERGY SYSTEMS
EUROPE
GEOTHERMAL SYSTEMS
GROUND WATER
HYDROGEN COMPOUNDS
HYDROTHERMAL SYSTEMS
NORTH AMERICA
OXYGEN COMPOUNDS
USA
WATER
WESTERN EUROPE
152004* - Geothermal Data & Theory- Isotope & Trace Element Studies
152001 - Geothermal Data & Theory- Properties of Aqueous Solutions
150200 - Geology & Hydrology of Geothermal Systems