Desert varnish: potential for age dating via uranium-series isotopes

Journal Article · Mon Dec 31 23:00:00 EST 1979 · J. Geol.; (United States)

DOI:https://doi.org/10.1086/628476· OSTI ID:6124417

Knauss, K G; Ku, T L

Trace metals and natural radioisotopes are measured in an unusually thick and presumed ancient desert varnish from the Colorado Plateau in Utah. Uranium and thorium concentrations in the sequence: varnish-altered rind-heartrock (Shinarump formation sandstone) indicate that uranium with little accompanying thorium is derived from external sources. The varnish forms a closed system for /sup 230/Th and /sup 231/Pa with equilibrium values for both /sup 230/Th//sup 234/U and /sup 231/Pa//sup 235/U. Selective leaching of the ferromanganese oxides followed by analysis of both the leachate and silicate residue is proposed to allow age determinations.

• Research Organization: Univ. of California, Livermore
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6124417
• Journal Information: J. Geol.; (United States), Journal Name: J. Geol.; (United States) Vol. 88; ISSN JGEOA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600 -- Radiation Chemistry
510100* -- Environment
Terrestrial-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
AGE ESTIMATION
ALPHA DECAY RADIOISOTOPES
ARID LANDS
DATA
DESERTS
DIMENSIONS
DISSOLUTION
ELEMENTS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
GEOLOGY
GROUND WATER
HEAVY NUCLEI
HYDROGEN COMPOUNDS
INFORMATION
ISOTOPE APPLICATIONS
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
LEACHING
MANGANESE COMPOUNDS
MANGANESE SILICATES
METALS
NATURAL RADIOACTIVITY
NORTH AMERICA
NUCLEI
NUMERICAL DATA
OXYGEN COMPOUNDS
QUANTITY RATIO
RADIOACTIVITY
RADIOISOTOPES
ROCKS
ROCKY MOUNTAIN REGION
SAMPLING
SANDSTONES
SEDIMENTARY ROCKS
SEPARATION PROCESSES
SILICATES
SILICON COMPOUNDS
THICKNESS
THORIUM 230
THORIUM ISOTOPES
TRACE AMOUNTS
TRANSITION ELEMENT COMPOUNDS
URANIUM 234
URANIUM ISOTOPES
USA
UTAH
WATER
YEARS LIVING RADIOISOTOPES