Radium isotope geochemistry of thermal waters, Yellowstone National Park, Wyoming, USA

Conference · Mon Mar 01 04:00:00 EST 1993 · Geochimica et Cosmochimica Acta; (United States)

OSTI ID:6524658

Sturchio, N C; Bohlke, J K; Markun, F J ^[1]

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1. Argonne National Lab., IL (United States)

Radium isotope activities ([sup 226]Ra, [sup 228]Ra, and [sup 224]Ra), chemical compositions, and sulfur isotope ratios in sulfate were determined for water samples from thermal areas in Yellowstone National Park, Wyoming. Activities of [sup 226]Ra in these waters range from <0.2 to 37.9 dpm/kg. Activity ratios of [sup 228]Ra/[sup 226]Ra range from 0.26 to 14.2, and those of [sup 224]Ra/[sup 228]Ra range from 0.73 to 3.1. Radium concentrations are inversely correlated with aquifer equilibration temperatures (estimated from dissolved silica concentrations), while [Ra/Ba][sub aq] and [sup 228]Ra/[sup 226]Ra activity ratios depend upon U/Ba and Th/U ratios in aquifer rocks. Major controls on Ra concentration in Yellowstone thermal waters are inferred to be (1) barite saturation (at Norris Geyser Basin, Mammoth Hot Springs, and other northern areas) and (2) zeolite-water ion exchange (at Upper Geyser Basin). The data are consistent with a model in which (1) radium and barium are supplied to water by bulk dissolution of aquifer rock, and (2) chemical equilibration of water with rock is rapid relative to the 1602 year half-life of [sup 226]Ra. The [sup 228]Ra/[sup 226]Ra activity ratios of the waters may in some cases reflect surface enrichments of [sup 232]Th and/or may indicate that [alpha]-recoil input of [sup 228]Ra is rapid relative to water-rock chemical equilibration. Activity ratios of [sup 224]Ra/[sup 228]Ra indicate a nearly ubiquitous [sup 224]Ra excess that generally increases with decreasing pH. Near-surface ([le]100 m) thermal water flow velocities at Mammoth Hot Springs are estimated from [sup 224]Ra/[sup 228]Ra variation to be [ge]1 m h[sup [minus]1]. 73 refs., 4 figs., 4 tabs.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6524658
• Report Number(s): CONF-911017--
• Conference Information: Journal Name: Geochimica et Cosmochimica Acta; (United States) Journal Volume: 57:6
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400100 -- Analytical &amp; Separations Chemistry
54 ENVIRONMENTAL SCIENCES
540220 -- Environment
Terrestrial-- Chemicals Monitoring &amp; Transport-- (1990-)
540330* -- Environment
Aquatic-- Radioactive Materials Monitoring &amp; Transport-- (1990-)
ACTIVITY LEVELS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ALPHA DECAY RADIOISOTOPES
BARITE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14 DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
ELEMENTS
EVEN-EVEN NUCLEI
HEAVY ION DECAY RADIOISOTOPES
HEAVY NUCLEI
INORGANIC ION EXCHANGERS
INTERNAL CONVERSION RADIOISOTOPES
ION EXCHANGE MATERIALS
ISOTOPE RATIO
ISOTOPES
MATERIALS
METALS
MINERALS
NONMETALS
NUCLEI
OXYGEN COMPOUNDS
PUBLIC LANDS
RADIOISOTOPES
RADIUM
RADIUM 224
RADIUM 226
RADIUM 228
RADIUM ISOTOPES
SILICATE MINERALS
SULFATE MINERALS
SULFATES
SULFUR
SULFUR COMPOUNDS
THERMAL WATERS
YEARS LIVING RADIOISOTOPES
YELLOWSTONE NATIONAL PARK
ZEOLITES