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K-Ar Age Values of Bulk Soil Samples and Clay Fractions: Effects of Acid Extraction and Implications for the Origin of Micaceous Clay in Savannah River Site Soils, South Carolina, USA

Understanding how natural Cs, Rb, and K have been redistributed in Savannah River Site (SRS) soils during pedogenesis is important to understanding how radiocesium released to the soils will behave over the long term. In this effort, it is important to distinguish K that has participated in mineral-water reactions from that still residing in primary silicate structures, particularly in the clay fraction. The impact of different degrees of acid extraction on K and radiogenic Ar in bulk soil and in clay from five SRS soil samples has been determined. Strong treatment (50% HNO3, three hours, 100°C) releases K from primary minerals, as shown also by a concomitant release of radiogenic Ar, but a more moderate treatment (6% HNO3, three hours, 80°C) does not release K. K in the clay fraction is mostly nonexchangeable K in remnants of primary mica, and clay K-Ar age values near 300 Ma indicate the mica originated in the Appalachian mountain belt.

Identiferoai:union.ndltd.org:GEORGIA/oai:digitalarchive.gsu.edu:geosciences_theses-1026
Date18 August 2010
CreatorsNaumann, Thomas E
PublisherDigital Archive @ GSU
Source SetsGeorgia State University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceGeosciences Theses

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