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Radiocarbon dating as a tool for hydrogeological investigations in the Palouse Basin Item Info

Radiocarbon dating is an important tool for understanding residence time, or ''age'' of ground water in an aquifer system. This thesis presents the results of a radiocarbon dating study completed in the Palouse Basin of eastern Washington and northern Idaho. The ground water age or residence time, implies the amount of time elapsed between ground water recharge and the time when the ground water sample was collected. Estimates of ground water age typically require extensive interpretations of physical, chemical and biological processes that act on 14C and should not be considered as a true age, but rather as a ''model age.'' Thirty-one samples were collected throughout the Palouse Basin between 2001 and 2003, in the loess, granite, Wanapum basalts, and primarily the Grande Ronde basalts. In the Palouse Basin, 14C concentrations indicate generally increasing age with increasing depth below the land surface. Relative ages of the ground water in the four major pumping centers range from oldest in the Palouse and Moscow areas to youngest in the Pullman and Colfax areas. Historically, nonpumping water levels throughout the basin have shown relatively flat horizontal gradients compared to steep, vertical gradients, suggesting relatively high horizontal hydraulic conductivity in the basalt aquifers, and very low vertical hydraulic conductivity in the interiors of basalt flows. It is conceptualized that the Palouse Basin is characteristically shaped like a ''bathtub'' filled with basalt lava flows and interbedded sediments. Vertical ground water recharge to the deep basalt aquifers is dominated by extremely slow vertical migration rates relative to current pumping withdrawals.

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Title:
Radiocarbon dating as a tool for hydrogeological investigations in the Palouse Basin
Authors:
Douglas, Alyssa A.
Date Created (ISO Standard):
2004-05
Description:
Radiocarbon dating is an important tool for understanding residence time, or ''age'' of ground water in an aquifer system. This thesis presents the results of a radiocarbon dating study completed in the Palouse Basin of eastern Washington and northern Idaho. The ground water age or residence time, implies the amount of time elapsed between ground water recharge and the time when the ground water sample was collected. Estimates of ground water age typically require extensive interpretations of physical, chemical and biological processes that act on 14C and should not be considered as a true age, but rather as a ''model age.'' Thirty-one samples were collected throughout the Palouse Basin between 2001 and 2003, in the loess, granite, Wanapum basalts, and primarily the Grande Ronde basalts. In the Palouse Basin, 14C concentrations indicate generally increasing age with increasing depth below the land surface. Relative ages of the ground water in the four major pumping centers range from oldest in the Palouse and Moscow areas to youngest in the Pullman and Colfax areas. Historically, nonpumping water levels throughout the basin have shown relatively flat horizontal gradients compared to steep, vertical gradients, suggesting relatively high horizontal hydraulic conductivity in the basalt aquifers, and very low vertical hydraulic conductivity in the interiors of basalt flows. It is conceptualized that the Palouse Basin is characteristically shaped like a ''bathtub'' filled with basalt lava flows and interbedded sediments. Vertical ground water recharge to the deep basalt aquifers is dominated by extremely slow vertical migration rates relative to current pumping withdrawals.
Subjects:
groundwater dating groundwater recharge groundwater discharge
Location:
Palouse
Latitude:
46.88
Longitude:
-117.17
Collection:
Palouse Basin
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
wbv
Date Digitized:
2012

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Source
Preferred Citation:
"Radiocarbon dating as a tool for hydrogeological investigations in the Palouse Basin", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-2004_douglas_radiocarbon_dating_as_a_tool.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
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