Status of volcanic hazard studies for the Nevada Nuclear Waste Storage Investigations. Volume II
Volcanic hazard investigations during FY 1984 focused on five topics: the emplacement mechanism of shallow basalt intrusions, geochemical trends through time for volcanic fields of the Death Valley-Pancake Range volcanic zone, the possibility of bimodal basalt-rhyolite volcanism, the age and process of enrichment for incompatible elements in young basalts of the Nevada Test Site (NTS) region, and the possibility of hydrovolcanic activity. The stress regime of Yucca Mountain may favor formation of shallow basalt intrusions. However, combined field and drill-hole studies suggest shallow basalt intrusions are rare in the geologic record of the southern Great Basin. The geochemical patterns of basaltic volcanism through time in the NTS region provide no evidence for evolution toward a large-volume volcanic field or increases in future rates of volcanism. Existing data are consistent with a declining volcanic system comparable to the late stages of the southern Death Valley volcanic field. The hazards of bimodal volcanism in this area are judged to be low. The source of a 6-Myr pumice discovered in alluvial deposits of Crater Flat has not been found. Geochemical studies show that the enrichment of trace elements in the younger rift basalts must be related to an enrichment of their mantle source rocks. This geochemical enrichment event, which may have been metasomatic alteration, predates the basalts of the silicic episode and is, therefore, not a young event. Studies of crater dimensions of hydrovolcanic landforms indicate that the worst case scenario (exhumation of a repository at Yucca Mountain by hydrovolcanic explosions) is unlikely. Theoretical models of melt-water vapor explosions, particularly the thermal detonation model, suggest hydrovolcanic explosion are possible at Yucca Mountain. 80 refs., 21 figs., 5 tabs.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 59818
- Report Number(s):
- LA-9325-MS-Vol.2; ON: DE86008326
- Resource Relation:
- Other Information: PBD: Jan 1986
- Country of Publication:
- United States
- Language:
- English
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SYSTHESIS OF VOLCANISM STUDIES FOR THE YUCCA MOUNTAIN SITE CHARACTERIZATION PROJECT
Volcanism Studies: Final Report for the Yucca Mountain Project
Related Subjects
05 NUCLEAR FUELS
YUCCA MOUNTAIN
VOLCANISM
GEOCHEMISTRY
BASALT
CHEMICAL COMPOSITION
MAGMA
INTRUSION
ROCK-FLUID INTERACTIONS
DETONATIONS
EXPLOSIONS
RADIOACTIVE WASTE DISPOSAL
RISK ASSESSMENT
TECTONICS
ISOTOPE RATIO
STRONTIUM 86
NEODYMIUM 143
NEODYMIUM 144
TRACE AMOUNTS
PARTICLE SIZE
EXPERIMENTAL DATA
Yucca Mountain Project