Radon sources emanation in granitic soil and saprolite

Conference · Sun Aug 01 00:00:00 EDT 1993

OSTI ID:10188404

Wollenberg, H; Flexser, S ^[1]; Brimhall, G; Lewis, C ^[2]

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1. Lawrence Berkeley Lab., CA (United States)
2. California Univ., Berkeley, CA (United States). Dept. of Geology and Geophysics

Petrological and geochemical examinations of soil, saprolite, and quartz diorite protolith have been made at the Small Structures field site, Ben Lomond Mountain, California. Variations in Ra in soil and saprolite are mainly controlled by heterogeneities inherited from the parent quartz diorite. Fission-track radiography shows that U is concentrated in the primary accessory minerals, zircon and sphene. However, most importantly for Rn emanation, U is also concentrated in secondary sites: weathered sphene, biotite and plagioclase, grain coatings, and Fe-rich fracture linings which also contain a rare-earth phosphate mineral. This occurrence of U along permeable fracture zones suggests that soil-gas Rn from depth (> 2 m) is a significant contributor to Rn availability near the surface. Zones highest in emanation occur where fine pedogenic phases: gibbsite, amorphous silica, and iron oxyhydroxide are most abundant. Mass balance analyses of this soil-saprolite profile are in progress and preliminary indicate that a high-emanation zone corresponds to the upper portion of a zone of accumulation of U and Ba.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10188404
• Report Number(s): LBL-34461; CONF-9309191-1; ON: DE94001256; TRN: AHC29313%%19
• Resource Relation: Conference: International radon conference,Denver, CO (United States),20-23 Sep 1993; Other Information: PBD: Aug 1993
• Country of Publication: United States
• Language: English

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