| Abstract: | Profiles of 4He in pore water were measured in clay aquitards in SW Ontario. The 4He distributions are consistent with groundwater velocities that are <6 mm yr-1, and thus diffusion is the dominant transport mechanism for 4He. Modeling indicates that the effective diffusion coefficient for 4He is 6.3 ?? 1.6 x 10 -6 cm2 s-1. Furthermore, the profiles are consistent with the internal release of 4He from aquitard sediments at a rate of 0.03-0.13 ??cc(STP) kg-1 yr-1. These rates are also consistent with laboratory release experiments and, on average, are 600 times greater than the production of 4He from U/Th decay. Modeling and the ratio of 21Ne to 4He within the sediments indicate that although the aquitards were deposited about 13 kA BP, the sediments released >70% of initial 4He for 50 to 60 kA prior to incorporation into the till. |
| Genre: | Article |
| ProdID: | 70025029 |
| Citation Author: | Sheldon, A. L.; Solomon, D. K.; Poreda, R. J.; Hunt, A. |
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| Citation Issue: | 12 |
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| Citation Language: | English |
| Citation Larger Work Title: | Water Resources Research |
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| Citation Search Results Text: | Radiogenic helium in shallow groundwater within a clay till, southwestern Ontario; 2003; Article; Journal; Water Resources Research; Sheldon, A. L.; Solomon, D. K.; Poreda, R. J.; Hunt, A. |
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| Citation Volume: | 39 |
| Citation Year: | 2003 |
| Type: | citation/reference |
| Text: | Radiogenic helium in shallow groundwater within a clay till, southwestern Ontario; 2003; Article; Journal; Water Resources Research; Sheldon, A. L.; Solomon, D. K.; Poreda, R. J.; Hunt, A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 2003 00:00 -0600 |
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