RESEARCH PAPER
Selection of Suitable Data Sets Improves 230Th/U Dates of Dirty Material
1
University of Marburg, Karl-von-Frisch-Straβe 4, D-35032 Marburg, Germany
Online publication date: 2008-03-28
Publication date: 2008-01-01
Geochronometria 2008;30:69-77
KEYWORDS
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.
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