Effects of subsurface boiling and dilution on the isotopic compositions of Yellowstone thermal waters

Journal Article · Sat Sep 10 04:00:00 EDT 1977 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB082i026p03694· OSTI ID:7215600

Truesdell, A H; Nathenson, M; Rye, R O

Studies of isotope hydrology of geothermal systems have generally emphasized deep circulation of meteoric water, demonstrated by constancy of deuterium contents, and an 'oxygen isotope shift' to higher oxygen 18 contents produced by water-rock reactions. However, subsurface boiling (in high-temperature systems) and dilution may cause deuterium (and oxygen 18) contents of hot spring and recharge waters to differ significantly. By using thermodynamic and isotopic fractionation data for water and steam the differences in chloride, oxygen 18, and deuterium between surface and deep thermal waters have been calculated for 'single-stage' (in which steam remains mixed with water and separates near a single temperature) and 'continuous' (in which steam is separated as it is formed) steam separation. Although changes in chloride concentration resulting from these processes are nearly identical, isotopic changes differ greatly. Single-stage steam separation from 250/sup 0/ to 95/sup 0/C results in increases in Cl, 10/sup 3/ ln ..delta../sup 18/O, and 10/sup 3/ ln ..delta..D(..delta..=(10/sup 3/+delta/sub surf/)/ (10/sup 3/+delta/sub deep/))) of 1.44 times, 1.75 0/00, and 9.1 0/00, respectively, whereas continuous steam separation results in increases of 1.41 times, 1.05 0/00, and 3.1 0/00. Because of these effects, deuterium contents of hot springs may be substantially higher than those of recharging waters, and part of the observed oxygen isotope shift may be due to boiling. The diverse compositions observed could result from boiling with 'multiple-stage' (intermediate between single-stage and continuous) steam separation of mixtures of a single deep thermal water (360/sup 0/C, 310 ppm Cl, and -149 0/00 deltaD) with cold dilute (5/sup 0/C, 2 ppm Cl) meteoric waters differing in deuterium according to locality (Norris, -142 0/00; Lower, -144 0/00; and Shoshone, -133 0/00). The recharge to the deep thermal water must be precipitation remote from the geyser basins or ancient precipitation from a colder period.

• Research Organization: U.S. Geological Survey, Menlo Park, California 94025
• OSTI ID: 7215600
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 82:26; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150302* -- Geothermal Exploration & Exploration Technology-- Geochemical Techniques & Surveys
BOILING
CHLORIDES
CHLORINE COMPOUNDS
DEUTERIUM
EVEN-EVEN NUCLEI
FLUIDS
GEOTHERMAL FLUIDS
GEOTHERMAL SYSTEMS
HALIDES
HALOGEN COMPOUNDS
HEAT FLOW
HOT-WATER SYSTEMS
HYDROGEN ISOTOPES
HYDROTHERMAL SYSTEMS
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
NATURAL STEAM
NUCLEI
ODD-ODD NUCLEI
OXYGEN 18
OXYGEN ISOTOPES
PHASE TRANSFORMATIONS
PUBLIC LANDS
STABLE ISOTOPES
STEAM
THERMAL WATERS
YELLOWSTONE NATIONAL PARK