Age and uranium content of soil micas from Antarctica by the fission particle track replica method

Journal Article · Fri Apr 01 04:00:00 EST 1977 · Soil Sci.; (United States)

DOI:https://doi.org/10.1097/00010694-197704000-00005· OSTI ID:5254824

Jackson, M L; Lee, S Y; Ugolini, F C; Helmke, P A

A replica method was developed for fission particle track age dating and determination of uranium content of micas in a Wright Valley, Antarctica, soil and parent rock. The mica particles in the soil were relatively small, fragile, and easily dissolved by chemical etchings. Muscovite mica flakes were therefore used as a replicating substrate to register induced fission tracks of the soil mica. The micas from three soil horizons (0 to 10, 10 to 30, and 30 to 50 cm depths) and parent rock, in four size fractions (100 to 500, 2 to 5, 0.2 to 2, and <0.2..mu..m) were examined to illustrate use of the method. The fission track age of the soil mica particles was 4.1 +- 0.2 million years (MY), slightly older than the minimum landscape (glacial bench) age of 3.7 +- 0.2 MY obtained previously by K-Ar dating of a volcanic cone formed after the glacial valley was formed. The ages of the 2 to 5, 0.2 to 2, and <0.2..mu..m fractions were the same as for the 100 to 500 ..mu..m flakes, when the spontaneous track density was calculated from that of the latter, in proportion to the U content. The fission track age of parent rock mica was 151 million years. The U content of the soil mica was 0.5 to 1.6 ppM which is 20 to 50 times higher than that of mica from the parent rock (0.03 ppM). The mica in the soil appears from age and petrographic thin-section results to be of pedogenic origin, formed by replacement in feldspars after the bench was carved. The fission particle track replica method is useful for age-dating of micas in soils, for determining trace amounts of uranium in micas, and for study of soil genesis in the Antarctic cold desert.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 5254824
• Journal Information: Soil Sci.; (United States), Journal Name: Soil Sci.; (United States) Vol. 123:4; ISSN SOSCA
• Country of Publication: United States
• Language: English

Related Subjects

050100* -- Nuclear Fuels-- Reserves
Exploration
&amp; Mining
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400103 -- Radiometric &amp; Radiochemical Procedures-- (-1987)
ACTINIDES
AGE ESTIMATION
ANTARCTIC REGIONS
ANTARCTICA
CHEMICAL ANALYSIS
CHEMISTRY
ELEMENTS
FISSION TRACKS
METALS
MICA
MINERALS
NATURAL OCCURRENCE
PARTICLE TRACKS
POLAR REGIONS
QUANTITATIVE CHEMICAL ANALYSIS
ROCKS
SOIL CHEMISTRY
SOILS
URANIUM