One million year old groundwater in the Sahara revealed by krypton-81 and chlorine-36

• Published in: Geophysical research letters Vol. 31; no. 5; pp. L05503 - n/a
• Main Authors: Sturchio, N. C., Du, X., Purtschert, R., Lehmann, B. E., Sultan, M., Patterson, L. J., Lu, Z.-T., Müller, P., Bigler, T., Bailey, K., O'Connor, T. P., Young, L., Lorenzo, R., Becker, R., El Alfy, Z., El Kaliouby, B., Dawood, Y., Abdallah, A. M. A.
• Format: Journal Article
• Language: English
• Published: American Geophysical Union 16-03-2004; Blackwell Publishing Ltd
• Subjects: General or Miscellaneous; Geochemistry; Geochronology; Groundwater transport; Hydrology; Techniques applicable in three or more fields; Egypt, Arab Rep; A, Atlantic
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2003GL019234

Measurements of 81Kr/Kr in deep groundwater from the Nubian Aquifer (Egypt) were performed by a new laser‐based atom‐counting method. 81Kr ages range from ∼2 × 105 to ∼1 × 106 yr, correlate with 36Cl/Cl ratios, and are consistent with lateral flow of groundwater from a recharge area near the Uweinat Uplift in SW Egypt. Low δ2H values of the 81Kr‐dated groundwater reveal a recurrent Atlantic moisture source during Pleistocene pluvial periods. These results indicate that the 81Kr method for dating old groundwater is robust and such measurements can now be applied to a wide range of hydrologic problems.