One million year old groundwater in the Sahara revealed by krypton-81 and chlorine-36
Abstract
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.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- March 2004
- DOI:
- 10.1029/2003GL019234
- arXiv:
- arXiv:physics/0402092
- Bibcode:
- 2004GeoRL..31.5503S
- Keywords:
-
- Geochemistry: Geochronology;
- Hydrology: Groundwater transport;
- General or Miscellaneous: Techniques applicable in three or more fields;
- Physics - Geophysics;
- Physics - Atomic Physics
- E-Print:
- doi:10.1029/2003GL019234