{"paper":{"title":"One million year old groundwater in the Sahara revealed by krypton-81 and chlorine-36","license":"","headline":"","cross_cats":["physics.atom-ph"],"primary_cat":"physics.geo-ph","authors_text":"A.M.A. Abdallah, B.E. Lehmann, B. El Kaliouby, K. Bailey, L.J. Patterson, L. Young, M. Sultan, N.C. Sturchio, P. Mueller, R. Becker, R. Lorenzo, R. Purtschert, T. Bigler, T.P. O'Connor, X. Du, Y. Dawood, Z. El Alfy, Z.-T. Lu","submitted_at":"2004-02-18T17:31:17Z","abstract_excerpt":"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 \\~2x10^5 to ~1x10^6 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 delta-2H 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 hydrologi"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"physics/0402092","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}