Effects of glacial ice on subsurface temperatures of hydrothermal systems in Yellowstone National Park, Wyoming: Fluid-inclusion evidence

Journal Article · Thu Dec 01 00:00:00 EST 1988 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1988)016<1077:EOGIOS>2.3.CO;2· OSTI ID:7262285

Bargar, K E; Fournier, R O ^[1]

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1. Geological Survey, Menlo Park, CA (USA)

Hydrothermal quartz and fluorite crystals containing liquid-rich fluid inclusions (coexisting vapor-rich fluid inclusions were not observed) were found in drill cores from eight relatively shallow research holes drilled by the US Geological Survey in and near major geyser basins of Yellowstone National Park. Homogenization temperatures (T{sub h}) for mostly secondary fluid inclusions show variations in temperature that have occurred at give depths since precipitation of the host minerals. Within major hydrothermal upflow zones, fluid-inclusion T{sub h} values all were found to be equal to or higher (commonly 20-50 C and up to 155 C higher) than present temperatures at the depths sampled. During periods when thick glacial ice covered the Yellowstone National Park region, pore-fluid pressures in the underlying rock were increased in proportion to the weight of the overlying column of ice. Accordingly, theoretical reference boiling-point curves that reflect the maximum temperature attainable in a hot-water geothermal system at a given depth were elevated, and temperatures within zones of major hydrothermal upflow (drill holes Y-2, Y-3, Y-6, Y-11, Y-13, and upper part of Y-5) increased. The thicknesses of ice required to elevate boiling-point curves sufficiently to account for the observed fluid-inclusion T{sub h} values are within the ranges estimated by glacial geologic studies. At the margins of major hydrothermal upflow zones (drill holes Y-4 and Y-9), fluid-inclusion T{sub h} values at given depths range from 57 C lower to about the same as the current temperature measurements because of a previous decrease in the rate of discharge of warm water and/or an increase in the rate of recharge of cold water into the hydrothermal system.

• OSTI ID: 7262285
• Journal Information: Geology; (USA), Vol. 16:12; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
HYDROTHERMAL SYSTEMS
PALEOTEMPERATURE
YELLOWSTONE NATIONAL PARK
DRILL CORES
ENVIRONMENTAL EFFECTS
FLUORITE
GLACIERS
ICE
INCLUSIONS
PORE PRESSURE
QUARTZ
RESERVOIR FLUIDS
TEMPERATURE MEASUREMENT
WEIGHT
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CHALCOGENIDES
ENERGY SYSTEMS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GEOTHERMAL SYSTEMS
HALIDE MINERALS
HALIDES
HALOGEN COMPOUNDS
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PUBLIC LANDS
SILICON COMPOUNDS
SILICON OXIDES
150200* - Geology &amp; Hydrology of Geothermal Systems
152000 - Geothermal Data &amp; Theory