Alteration minerals in granitic rock at Ashio as radionuclide adsorption materials
- Geological Survey of Japan, Tsukuba (Japan)
- National Research Inst. for Earth Science and Disaster Prevention, Tsukuba (Japan)
Alteration minerals from a drill-core (maximum depth 2,002 m) in the granitic rock at Ashio, central Japan, were studied by optical microscopy, X-ray diffractometry and analytical scanning electron microscopy. In the host rock, biotite is altered to chlorite and plagioclase to illite. Calcite has precipitated in veinlets and grain boundaries. The host rock close to fractures is strongly altered, whereas the rocks distant from fractures are less altered. Quartz, illite, chlorite, laumontite and calcite have precipitated on fracture walls. The alteration minerals are estimated to have formed in the range 140--200 C, higher than the present temperature (13--96 C). The chemical composition of the ground water in the granitic rock at Ashio was estimated thermodynamically from the mineral assemblage. The alteration reaction of plagioclase and the precipitation of calcite may occur simultaneously. The alteration minerals formed in the host rock and in the fractures may adsorb radionuclides effectively, and thus may inhibit radionuclide transport to biosphere.
- OSTI ID:
- 382910
- Report Number(s):
- CONF-941075-; ISBN 1-55899-253-7; TRN: 96:025802
- Resource Relation:
- Conference: 18. international symposium on the scientific basis for nuclear waste management, Kyoto (Japan), 23-27 Oct 1994; Other Information: PBD: 1995; Related Information: Is Part Of Scientific basis for nuclear waste management 18. Part 2; Murakami, Takashi [ed.] [Ehime Univ., Matsuyama, Ehime (Japan). Dept. of Earth Sciences]; Ewing, R.C. [ed.] [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences]; PB: 690 p.; Materials Research Society symposium proceedings, Volume 353
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GRANITES
HYDROTHERMAL ALTERATION
JAPAN
GEOLOGIC FORMATIONS
MINERALOGY
MINERALS
RADIONUCLIDE MIGRATION
GEOLOGIC FRACTURES
HIGH-LEVEL RADIOACTIVE WASTES
VITRIFICATION
RADIOACTIVE WASTE DISPOSAL
UNDERGROUND DISPOSAL
DRILL CORES
QUARTZ
FELDSPARS
ANORTHOSITES
BIOTITE
CALCITE
LAUMONTITE
CHLORITE MINERALS
ILLITE
SORPTIVE PROPERTIES
GROUND WATER
WATER CHEMISTRY