Hostname: page-component-745bb68f8f-cphqk Total loading time: 0 Render date: 2025-01-08T15:39:31.322Z Has data issue: false hasContentIssue false
  • English
  • Français

Radiocarbon Dating of Groundwater in a Confined Aquifer in Southeast Arizona

Published online by Cambridge University Press:  18 July 2016

Frederick N. Robertson
Frederick N. Robertson*
Affiliation:
U.S. Geological Survey, 375 South Euclid Avenue, Tucson, Arizona 85719 USA
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Radiocarbon, δ13C and major-element data were used to construct a geochemical framework for interpretation of the hydrological flow system in the lower San Pedro basin, southeastern Arizona, USA. The 14C and major-element data show a regional confined aquifer that extends throughout most of the basin. Groundwater ages, after correcting for chemistry, are greater than 10 ka bp. The groundwater ages do not increase in a downvalley direction, the assumed direction of groundwater movement in most intermontane basins in the region, but along general flow paths normal to the mountains toward the center of the basin. Recharge to the confined aquifer originates from infiltration of precipitation and runoff near the alluvium-mountain contact along the Galiuro Mountains and is discharged by evapotranspiration along the center of the basin. The hydrogeological concept of the 14C model is supported by the water chemistry and by the mass transfer defined by the chemical model. Weathering of primary silicate minerals in the confined aquifer does not occur downvalley, but only along the direction of flow. Hydraulic conductivities calculated for the aquifer from 14C velocities are about an order of magnitude slower than those determined through hydrological methods. The lower hydraulic-conductivity values are attributed to a thick confining layer overlying the discharge area along the San Pedro River.

Type
II. Applied Isotope Geochemistry
Information
Radiocarbon , Volume 34 , Issue 3: Proceedings of the 14th International Radiocarbon Conference , 1992 , pp. 664 - 676
Copyright
Copyright © The American Journal of Science 

References

Anderson, T. W., Freethey, G. W. and Tucci, P. 1990 Geohydrology and water resources of alluvial basins in south-central Arizona and parts of adjacent States. U.S. Geological Survey Open-File Report 89–378: 99 p.Google Scholar
Ball, J. W., Nordstrom, D. K. and Zachmann, D. W. 1987 WATEQ4F – A personal computer Fortran translation of the geochemical model WATEQ2 with revised data base. U.S. Geological Survey Open-File Report 87–50: 108 p.Google Scholar
Barnes, I. 1964 Field measurement of alkalinity and pH. U.S. Geological Survey Water-Supply Paper 1535-H: 17 p.Google Scholar
Brown, E., Skougstad, M. W. and Fishman, M. J. 1970 Methods for collection and analysis of water samples for dissolved minerals and gases. U.S. Geological Survey Techniques of Water Resources Investigations 5: 160 p.Google Scholar
Fritz, P., Fontes, J.-Ch., Frape, S. K., Louvat, D., Michelot, J.-L. and Balderer, W. 1989 The isotope geochemistry of carbon in groundwater at Stripa. Geochimica et Cosmochimica Acta 53: 1765–1775.CrossRefGoogle Scholar
Halpenny, L. C. and others 1952 Ground water in the Gila River basin and adjacent areas, Arizona – A summary. U.S. Geological Survey Open-File Report : 224 p.Google Scholar
Krieger, M. H. 1979 Ash-flow tuffs of the Galiuro Volcanics in the northern Galiuro Mountains, Pinal County, Arizona. U.S. Geological Survey Professional Paper 1104: 32 p.Google Scholar
Krieger, M. H. 1980 Zeolitization of Tertiary tuffs in lacustrine and alluvial deposits in the Ray-San Manuel area, Pinal and Gila Counties Arizona. In Shorter Contributions to Mineralogy and Petrology, 1979. U.S. Geological Survey Professional Paper 1124-D: 11 p.Google Scholar
Laney, R. L. and Hahn, M. E. 1987 Hydrogeology of the eastern part of the Salt River Valley area, Maricopa and Pinal Counties, Arizona. U.S. Geological Survey Water-Resources Investigations : 86–4147.Google Scholar
Parada, C. B. (ms.) 1981 Isotopic composition of soil carbon dioxide in the Tucson basin. , University of Arizona: 85 p.Google Scholar
Parkhurst, D. L., Plummer, L. N. and Thorstenson, D. C. 1982 BALANCE – A computer program for calculating mass transfer for geochemical reactions in ground water. U.S. Geological Survey Water-Resources Investigations 82–14: 29 p.Google Scholar
Phillips, F. M., Tansey, M. K. and Peeters, L. A. 1989 An isotopic investigation of groundwater in the central San Juan Basin, New Mexico – Carbon 14 dating as a basis for numerical flow modeling. Water Resources Research 25(10): 2259–2273.Google Scholar
Plummer, L. N., Parkhurst, D. L. and Thorstenson, D. C. 1983 Development of reaction models for groundwater systems. Geochimica et Cosmochimica Acta 47: 665–686.Google Scholar
Pool, D. R. 1986 Aquifer geology of alluvial basins of Arizona. In Anderson, T. W. and Johnson, A. I., eds., Regional Aquifer Systems of the United States, Southwest Alluvial Basins of Arizona. American Water Resources Association Monograph Series 7: 25–36.Google Scholar
Robertson, F. N. 1984 Solubility controls of fluorine, barium and chromium in ground water in alluvial basins of Arizona. In Hitchon, B. and Wallick, E. I., eds., Practical Applications of Groundwater Geochemistry. Proceedings of the 1st Canadian/American Conference on Hydrogeology: 96–102.Google Scholar
Robertson, F. N. 1991 Geochemistry of ground water in alluvial basins of Arizona and adjacent parts of Nevada, New Mexico, and California. U.S. Geological Survey Professional Paper 1406-C: 90 p.Google Scholar
Roeske, R. H. and Werrell, W. L. 1973 Hydrological conditions in the San Pedro River Valley, Arizona, 1971. Arizona Water Commission Bulletin 4: 76 p.Google Scholar
Thorstenson, D. C., Weeks, E. P., Haas, H. and Woodward, J. C. 1990 Physical and chemical characteristics of topographically affected airflow in an open borehole at Yucca Mountain, Nevada. In Proceedings of the Topical Meeting on Nuclear Waste Isolation in the Unsaturated Zone. America Nuclear Society, Inc., Grange Park, Illinois.Google Scholar
Turner, J. V. 1982 Kinetic fractionation of carbon-13 during calcium carbonate precipitation. Geochimica et Cosmochimica Acta 46: 1183–1191.CrossRefGoogle Scholar
Wallick, E. I. (ms.) 1973 Isotopic and chemical considerations in radiocarbon dating of groundwater within the arid Tucson basin, Arizona. Ph.D. dissertation, University of Arizona: 184 p.Google Scholar
Wigley, T. M. L., Plummer, L. N. and Pearson, F. J. Jr. 1978 Mass transfer and carbon isotope evolution of natural water systems. Geochimica et Cosmochimica Acta 42: 1117–1139.CrossRefGoogle Scholar
Wood, W. W. and Petraitis, M. J. 1984 Origin and distribution of carbon dioxide in the unsaturated zone of the Southern High Plains. Water Resources Research 20(9): 1193–1208.Google Scholar