Lead isotopic composition of paleozoic and late proterozoic marine carbonate rocks in the vicinity of Yucca Mountains, Nevada

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:145403

Zartman, R E; Kwak, L M ^[1]

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1. Geological Survey, Denver, CO (United States)

Paleozoic and Late Proterozoic marine carbonate rocks (limestones, dolomites, and their metamorphic equivalents) cropping out in the vicinity of Yucca Mountain contain lead with an isotopic composition strongly suggesting them to be a major source of the lead observed at Trench 14 in the carbonate phase of carbonate-silica veins and nearby surficial calcrete deposits. Six whole-rock samples of marine carbonate rocks yield {sup 206}Pb/{sup 204}Pb = 19.21-29.06, {sup 207}Pb/{sup 204}Pb = 15.74-16.01, and {sup 208}Pb/{sup 204}Pb = 37.90-39.25, and leachate and residue fractions of the rocks reveal additional isotopic heterogeneity within individual samples. Two samples of eolian dust also have isotopic compositions lying along a `carbonate` to `silicate` mixing trend that appears to arise entirely from pedeogenic processes. The tendency for the marine carbonate rocks to evolve highly uranogenic, but not thorogenic, lead results in a distinctive isotopic composition that serves as a tracer in eolian dust and secondary carbonate minerals derived from the marine carbonate rocks.

• Research Organization: American Nuclear Society, La Grange Park, IL (United States); American Society of Civil Engineers, New York, NY (United States)
• OSTI ID: 145403
• Report Number(s): CONF-930408--Vol.2
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
58 GEOSCIENCES
CARBONATE ROCKS
GEOCHEMISTRY
ISOTOPE RATIO
LEAD ISOTOPES
RADIOACTIVE WASTE DISPOSAL
SITE CHARACTERIZATION
YUCCA MOUNTAIN
Yucca Mountain Project