| Abstract: | Average calculated noble gas temperatures increase from 10 to 22??C in groundwater from recharge to discharge areas in carbonate-rock aquifers of southern Nevada. Loss of noble gases from groundwater in these regional flow systems at flow barriers is the likely process that produces an increase in recharge noble gas temperatures. Emplacement of low permeability rock into high permeability aquifer rock and the presence of low permeability shear zones reduce aquifer thickness from thousands to tens of meters. At these flow barriers, which are more than 1,000 m lower than the average recharge altitude, noble gases exsolve from the groundwater by inclusion in gas bubbles formed near the barriers because of greatly reduced hydrostatic pressure. However, re-equilibration of noble gases in the groundwater with atmospheric air at the low altitude spring discharge area, at the terminus of the regional flow system, cannot be ruled out. Molecular diffusion is not an important process for removing noble gases from groundwater in the carbonate-rock aquifers because concentration gradients are small. |
| Genre: | Conference Paper |
| ProdID: | 70025995 |
| Citation Author: | Thomas, J. M.; Bryant, Hudson, G.; Stute, M.; Clark, J. F. |
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| Citation End Page: | 579 |
| Citation Issue: | 5 |
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| Citation Language: | English |
| Citation Larger Work Title: | Environmental Geology |
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| Citation Number Of Pages: | 12 |
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| Citation Search Results Text: | Noble gas loss may indicate groundwater flow across flow barriers in southern Nevada; 2003; Conference Paper; Environmental Geology; Thomas, J. M.; Bryant, Hudson, G.; Stute, M.; Clark, J. F. |
| Citation Start Page: | 568 |
| Citation Volume: | 43 |
| Citation Year: | 2003 |
| Type: | citation/reference |
| Text: | Noble gas loss may indicate groundwater flow across flow barriers in southern Nevada; 2003; Conference Paper; Environmental Geology; Thomas, J. M.; Bryant, Hudson, G.; Stute, M.; Clark, J. F. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 2003 00:00 -0600 |
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