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dc.contributor.authorLoosli, Heinz Hugo
dc.contributor.authorOeschger, Hans
dc.date.accessioned2021-02-11T19:32:19Z
dc.date.available2021-02-11T19:32:19Z
dc.date.issued1980-01-01
dc.identifier.citationLoosli, H. H., & Oeschger, H. (1980). Use of 39Ar and 14C for groundwater dating. Radiocarbon, 22(3), 863-870.
dc.identifier.issn0033-8222
dc.identifier.doi10.1017/S0033822200010250
dc.identifier.urihttp://hdl.handle.net/10150/652573
dc.descriptionFrom the 10th International Radiocarbon Conference held in Bern, Switzerland and Heidelberg, Germany, August 19-26, 1979.
dc.description.abstractCosmic-ray produced atmospheric 39Ar activity (T1/2 = 269 yr) has been determined at 0.11 +/- 0.012 dpm/lt argon. Ice samples from two profiles in Greenland bore holes showed conclusively that 39Ar dating leads to correct ages. Corrections can be made for possible contamination of the samples with ambient air during field extraction and during laboratory processing by measuring 85Kr in the same samples. The following isotopes: 14C, 39Ar, 85Kr, 3H, partly 32Si, 13C, and 18O were investigated in 20 groundwater samples. Unexpectedly large discrepancies between "14C ages" and "39Ar ages" were observed for many of these samples. For example, a horizontal profile of a confined sandstone aquifer in the Franconian Albvorland showed decreasing 39Ar and 14C activities from respectively, 100 percent to 17 percent and 80 percent to 0.3 percent of modern activity, corresponding to elapsed time periods of 700 and >20,000 years, respectively. It seems unlikely that gas exchange through the aquiclude is the cause of this discrepancy. It can neither be explained by only assuming that the water represents a mixing of components with different ages. We detected the possibility of underground production of 39Ar in thermal spring water from Zurzach, Switzerland. Its argon showed higher specific activity than atmospheric argon. Elsewhere, however, samples were found containing no detectable 39Ar activity: two wells of a confined carstic aquifer in Ingolstadt, Germany, show less than 7 percent atmospheric activity. In our opinion, the assumptions on which the 14C method in hydrology are based need to be critically re-examined. It is possible that for some aquifers carbonate exchange between solid and liquid phases in the aquifer changes 14C results to a larger degree than generally assumed.
dc.language.isoen
dc.publisherAmerican Journal of Science
dc.relation.urlhttp://radiocarbon.webhost.uits.arizona.edu/
dc.rightsCopyright © The American Journal of Science
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectAr 39
dc.subjectargon
dc.subjectnoble gases
dc.subjectArctic region
dc.subjectGreenland
dc.subjectsurveys
dc.subjectground water
dc.subjectmethods
dc.subjectgeochronology
dc.subjectC 14
dc.subjectcarbon
dc.subjectdates
dc.subjectisotopes
dc.subjectradioactive isotopes
dc.subjectabsolute age
dc.titleUse of 39Ar and 14C for Groundwater Dating
dc.typeProceedings
dc.typetext
dc.identifier.journalRadiocarbon
dc.description.noteThis material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.
dc.description.collectioninformationThe Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform February 2021
dc.source.volume22
dc.source.issue3
dc.source.beginpage863
dc.source.endpage870
refterms.dateFOA2021-02-11T19:32:19Z


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