Distribution of rubidium, strontium, and zirconium in tuff from two deep coreholes at Yucca Mountain, Nevada
Variations in concentrations of trace elements Rb, Sr, and Zr within the sequence of high-silica tuff and dacitic lava beneath Yucca Mountain reflect both primary composition and secondary alteration. Rb and K concentrations have parallel trends. Rb concentrations are significantly lower within intervals containing zeolitic nonwelded to partially welded and bedded tuffs and are higher in thick moderately to densely welded zones. Sr concentrations increase with depth from about 30 parts per million (ppM) in the Topopah Spring Member of the Paintbrush Tuff to almost 300 ppM in the older tuffs. Zr concentrations are about 100 ppM in the Topopah Spring Member and also increase with depth to about 150 ppM in the Lithic Ridge Tuff and upper part of the older tuffs. Conspicuous local high concentrations of Sr in the lower part of the Tram Member, in the dacite lava, and in unit c of the older tuffs in USW G-1, and in the densely welded zone of the Bullfrog Member in USW GU-3/G-3 closely correlate with high concentrations of less-mobile Zr and may reflect either primary composition or elemental redistribution resulting largely from smectitic alteration. Initial {sup 87}Sr/{sup 86}Sr values from composite samples increase upward in units above the Bullfrog Member of the Crater Flat Tuff. The progressive tenfold increase in Sr with depth coupled with the similarity of initial {sup 87}Sr/{sup 86}Sr values within the Bullfrog Member and older units to those of Paleozoic marine carbonates are consistent with a massive influx or Sr from water derived from a Paleozoic carbonate aquifer. 23 refs., 4 figs., 1 tab.
- Research Organization:
- US Geological Survey, Denver, CO (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (USA)
- DOE Contract Number:
- AI08-78ET44802
- OSTI ID:
- 138091
- Report Number(s):
- CONF-910435-76; ON: DE91011937; TRN: 91:018458
- Resource Relation:
- Conference: 2. annual American Nuclear Society (ANS) international high level radioactive waste management conference, Las Vegas, NV (United States), 28 Apr - 3 May 1991; Other Information: PBD: [1991]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Stratigraphy, structure, and some petrographic features of Tertiary volcanic rocks at the USW G-2 drill hole, Yucca Mountain, Nye County, Nevada
Stratigraphy and structure of volcanic rocks in drill hole USW-G1, Yucca Mountain, Nye County, Nevada