Fractionation of Zr and Hf in surface processes

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6874705

Chyi, L L; Garg, A N

Zircons from a pegmatite near Tuxedo, North Carolina were crushed and treated with different reagents under different conditions. The treated and untreated samples were determined for Zr and Hf with radiochemical neutron activation analysis. Zircons treated with 50% sulfuric acid were having lowered Zr content and Zr/Hf ratio. The conclusions are that a portion of Zr and Hf in zircons is sensitive to leaching, and Zr appears to be selectively leached over Hf. The conclusions of this work support the observations of small dissolutions of Zr in both acidic podzolic soils and in alkaline laterites, of lower Zr content in soils on glacial drift, and of lower Zr/Hf ratios in loess deposits from various parts of the world. The fractionation of Zr and Hf in surface processes appears to be due to selective leaching. Weakening of Zr-O over Hf-O bonds in zircon by fission projectiles is postulated to be the viable process. The observed fractionation from leaching experiments suggest that areas receiving leachates such as swamps, lakes, and oceans should have high to very high Zr/Hf ratios preserved in rocks. High ratios are found in the Springfield (No. 9) Coal, the Green River Shale, and various limestones. High ratio is also found in orchard leaves, which grow by absorbing leachate from soil.

• Research Organization: Univ. of Akron, OH (USA)
• OSTI ID: 6874705
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580400* -- Geochemistry-- (-1989)
ACTIVATION ANALYSIS
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMISTRY
DISSOLUTION
ELEMENTS
FEDERAL REGION IV
FRACTIONATION
GEOCHEMISTRY
GRANITES
HAFNIUM
IGNEOUS ROCKS
LEACHING
METALS
MINERALS
NORTH AMERICA
NORTH CAROLINA
OXYGEN COMPOUNDS
PEGMATITES
PLUTONIC ROCKS
QUANTITATIVE CHEMICAL ANALYSIS
ROCKS
SEPARATION PROCESSES
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SOIL CHEMISTRY
SOILS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
USA
ZIRCON
ZIRCONIUM
ZIRCONIUM COMPOUNDS
ZIRCONIUM SILICATES