<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">230Th/U dating of dirty material such as fen peat and secondary carbonates depends on the ability to select suitable and to discard unsuitable data sets before the calculation of 230Th/U ages. This means that open system conditions with respect to uranium during ageing are excluded and solely one source of detrital contamination was present in the samples. Three kinds of selection approaches of suitable data sets were applied: (1) isotope ratio plots, (2) the isotope-ratio evolution plot and the iterative determination of the decay-corrected initial detrital 230Th/232Th activity ratio (AR) as well as (3) depth profiles of the uranium concentration and the 234U/238U AR and the ash content. For reliable 230Th/U age dating of dirty material all selection procedures have to be commonly applied because none of them works perfectly.</abstract>

230Th/U dating of dirty material such as fen peat and secondary carbonates depends on the ability to select suitable and to discard unsuitable data sets before the calculation of 230Th/U ages. This means that open system conditions with respect to uranium during ageing are excluded and solely one source of detrital contamination was present in the samples. Three kinds of selection approaches of suitable data sets were applied: (1) isotope ratio plots, (2) the isotope-ratio evolution plot and the iterative determination of the decay-corrected initial detrital 230Th/232Th activity ratio (AR) as well as (3) depth profiles of the uranium concentration and the 234U/238U AR and the ash content. For reliable 230Th/U age dating of dirty material all selection procedures have to be commonly applied because none of them works perfectly.

Selection of Suitable Data Sets Improves 230Th/U Dates of Dirty Material

University of Marburg, Karl-von-Frisch-Straβe 4, D-35032 Marburg, Germany

Geochronometria

Selection of Suitable Data Sets Improves Th/U Dates of Dirty Material

230Th/U dating of dirty material such as fen peat and secondary carbonates depends on the ability to select suitable and to discard unsuitable data sets before...

Selection of Suitable Data Sets Improves ²³⁰Th/U Dates of Dirty Material

Publié en ligne: 28 mars 2008

Pages: 69 - 77

DOI: https://doi.org/10.2478/v10003-008-0001-1

Mots clés
uranium series dating, dirty material, peat, secondary carbonate

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