Geochemical studies of Columbia River basalts

Conference · Sun Jan 01 04:00:00 EST 1984 · Mater. Res. Soc. Symp. Proc.; (United States)

OSTI ID:5904124

Brookins, D G; Murphy, M T; Wollenberg, H A; Flexser, S

Two studies of Columbia River basalts that are relevant to US radwaste disposal programs are reported. A rhyodacite intrudes the Wanapum basalt and is exposed in a quarry along the Hood River, Oregon. Since the rhyodacite is different geochemically from the basalt, and was intruded at a high temperature, then this site can be used to evaluate the effects of the intrusion on the basalt. In such a study we assume the intrusive rock is a high temperature heat engine, and that cooling may be by convection, conduction, or both. Contact effects of the intrusion are not pronounced in the basalt, and are restricted to minor recrystallization within one meter of the contact, and to possibly some minor fracture filling. Traverses were made from the rhyodacite into the basalt, and samples at closely spaced intervals analyzed for K, U, Th by field and laboratory gamma spectrometry, and by neutron activation analysis for some 35 elements. Separate aliquotes were analyzed by isotope dilution to inspect Sr isotopic variations. The chemical studies do not indicate migration of any elements from the rhyodacite into the basalt, nor for any in-basalt or in-rhyodacite migration. Despite a pronounced chemical gradient between the rocks, each has remained a closed, isochemical system. The Sr isotopic studies indicate that the rhyodacite possesses Sr (87/86) = 0.70407 +/- 0.00008 while the intruded basalts possess Sr (87/86) = 0.7052 +/- 0.0002. Even in samples of the contact, with intermingled rhyodacite and basalt, each rock preserves its own characteristic Sr (87/86) signature, thus again attesting to the closed system conditions. It was concluded for this natural experiment that the Wanapum basalt is not readily penetrated by elements from a high temperature, molten source. 9 references, 4 figures, 3 tables.

• Research Organization: Univ. of New Mexico, Albuquerque
• OSTI ID: 5904124
• Report Number(s): CONF-831174-
• Conference Information: Journal Name: Mater. Res. Soc. Symp. Proc.; (United States) Journal Volume: 26
• Country of Publication: United States
• Language: English

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ACTINIDES
ACTIVATION ANALYSIS
ALKALI METALS
ALKALINE EARTH ISOTOPES
BARYON REACTIONS
BASALT
BETA DECAY RADIOISOTOPES
CHEMICAL ANALYSIS
COLUMBIA RIVER
DATA
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
ENVIRONMENTAL TRANSPORT
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
GAMMA SPECTROSCOPY
GEOCHEMICAL SURVEYS
HADRON REACTIONS
HOURS LIVING RADIOISOTOPES
HYDROLOGY
IGNEOUS ROCKS
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LICENSING
MANAGEMENT
MASS TRANSFER
MECHANICS
METALS
NEUTRON REACTIONS
NUCLEAR FACILITIES
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUMERICAL DATA
POTASSIUM
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE FACILITIES
RADIOISOTOPES
RADIONUCLIDE MIGRATION
RIVERS
ROCK MECHANICS
ROCKS
SITE SELECTION
SPECTROSCOPY
STABLE ISOTOPES
STREAMS
STRONTIUM 86
STRONTIUM 87
STRONTIUM ISOTOPES
SURFACE WATERS
SURVEYS
THORIUM
URANIUM
VOLCANIC ROCKS
WASTE DISPOSAL
WASTE MANAGEMENT