Applications of in situ cosmogenic nuclides in the geologic site characterization of Yucca Mountain, Nevada

Conference · Thu Aug 01 04:00:00 EDT 1996

OSTI ID:264483

Gosse, J C; Harrington, C D ^[1]; Whitney, J W ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Geological Survey, Denver, CO (United States). Federal Center

The gradual buildup of rare isotopes from interactions between cosmic rays and atoms in an exposed rock provides a new method of directly determining the exposure age of rock surfaces. The cosmogenic nuclide method can also provide constraints on erosion rates and the length of time surface exposure was interrupted by burial. Numerous successful applications of the technique have been imperative to the complete surface geologic characterization of Yucca Mountain, Nevada, a potential high level nuclear waste repository. The {sup 10}Be exposure age of Black Cone lava, within a ten mile radius of the proposed repository site, is 840 {+-} 210 kyr (in agreement with previous K/Ar dates of 1.0 {+-} 0.1 Ma). Rates of erosion of the tuff bedrock (< 0.4 cm/kyr from 7 {sup 10}Be measurements) and of hillslope colluvium ({approximately} 0.5 cm/kyr from {sup 10}Be dates on boulder deposits) preclude denudation of the mountain as a concern. Neotectonic concerns (rate of slip and timing of last significant movement along faults) are also being addressed with in situ {sup 14}C and {sup 10}Be measurements on scarp surfaces and on fault-dissected landforms where no surficial expression of the fault is preserved.

• OSTI ID: 264483
• Report Number(s): CONF-951155--; ISBN 1-55899-315-0
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
BERYLLIUM 10
CARBON 14
COSMIC RADIATION
HIGH-LEVEL RADIOACTIVE WASTES
ISOTOPE DATING
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE FACILITIES
SITE CHARACTERIZATION
UNDERGROUND DISPOSAL
YUCCA MOUNTAIN