{
  "annotation_id": "bb2b167b-c7cf-44f0-8c3f-b2b1bdc4f1bc",
  "date_created": "2026-03-02T18:00:50.152000Z",
  "date_modified": "2026-03-02T18:00:50.152000Z",
  "file_hash": "4a19e4c8d0eacbf8047b5faad51a1085102dcf962710c54e90671470204ed68e",
  "private": false,
  "record": {
    "abstract": "Measurements of 81Kr/Kr in deep groundwater from the Nubian Aquifer (Egypt)\nwere performed by a new laser-based atom-counting method. 81Kr ages range from\n\\~2x10^5 to ~1x10^6 yr, correlate with 36Cl/Cl ratios, and are consistent with\nlateral flow of groundwater from a recharge area near the Uweinat Uplift in SW\nEgypt. Low delta-2H values of the 81Kr-dated groundwater reveal a recurrent\nAtlantic moisture source during Pleistocene pluvial periods. These results\nindicate that the 81Kr method for dating old groundwater is robust and such\nmeasurements can now be applied to a wide range of hydrologic problems.",
    "arxiv_id": "physics/0402092",
    "authors": [
      "N. C. Sturchio",
      "X. Du",
      "R. Purtschert",
      "B. E. Lehmann",
      "M. Sultan",
      "L. J. Patterson",
      "Z. -T. Lu",
      "P. Mueller",
      "T. Bigler",
      "K. Bailey",
      "T. P. O\u0027Connor",
      "L. Young",
      "R. Lorenzo",
      "R. Becker",
      "Z. El Alfy",
      "B. El Kaliouby",
      "Y. Dawood",
      "A. M. A. Abdallah"
    ],
    "categories": [
      "physics.geo-ph",
      "physics.atom-ph"
    ],
    "doi": "10.1029/2003GL019234",
    "title": "One million year old groundwater in the Sahara revealed by krypton-81   and chlorine-36",
    "url": "https://arxiv.org/abs/physics/0402092"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "19622a5d-d23c-471e-b8d6-5f2538718738",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}