Propozycja ujednolicenia sposobu podawania i cytowania wyników datowania osadów metodą TL

Abstract

QUOTATIONS OF TL DATING OF SEDIMENTS: A PROPOSAL OF UNIFICATION Summary Development of the thermoluminescence (TL) method of dating applied to Quaternary sediments demands to undertake some resolutions concerning the unification of quotation of TL dates in all publications in the field of Quaternary palaeogeography and stratigraphy. Such a unification seems to be necessary since the TL method of dating sediments cannot be regarded as standard routine method of dating, and results of dating are not independent of the versions of laboratory procedures used, and, moreover, are also influenced by a number of poorely known extralaboratory factors. Present paper contains a proposal of a convention which is addressed to the authors, the reviewers and the editors of all publications in the field of Quaternary studies. Basing on methodological achievements in the field of radiocarbon dating, and taking into account the convention of quotation of TL dates of ancient pottery formulated by Fleming (1978, 1979) as well as available examples of quotation of TL dates of sediments in recent papers published in some outstanding international journals, the authors of this paper propose the following unified form of quotation of TL dates: age ± error ka [lab. no.: mineral; fraction] [method used to ev. ED ; method used to ev. Dre (value of Dre)] [other factors] This form contains four separate segments which include logical sequence of data concerning the result and the method of dating. Segment A contains the result (= age) with the dating error, and appropriate unit. We propose to quote the TL age and dating error in thousands of years (= ka), i.e. for example 30,0 ±4,5 ka instead of 30 000 ±4500 years. Segment B includes basic parameters necessary for identification of the measurement: laboratory number, name of the mineral used and the grain size (in μm). We propose following denotations for the minerals which are commonly used in TL dating : q - quartz, s - feldspar, c - calcite, pm - polimineral fraction. Segment C contains fundamental information on the method of age determination and includes two subsegments: Cl - name of the method used to evaluate the equivalent dose (ED) with additional information (in parenthesis) whether or not the plateau test (tp) was performed, and, if so, with the corresponding temperature interval stated; C2 - presents name of the method used to evaluate the equivalent dose rate (Dre) with its value, standard error and the unit of Dre• Short standard denotations are proposed for the most frequently used methods of DE determination, i.e. additive method, regeneration method, and the R-Γ method, accounting for different technical versions of these methods. Similarly, short denotations are proposed for nine methods which are of potential use in determining Dre. We propose that the value of Dre should be quoted in Gy/ka or μGy/a. Segment D contains information on other factors considered which could influence the result of TL dating. It contains undetermined number of parameters, in particular it can contain no element (= lack of segment D). We propose short standard denotations for eight most relevant factors which should - when necessary - be accounted for in TL dating of sediments. Described convention of quotation of TL dates does not forejudge technical and editorial aspects of its use in publications. We propose only that all the TL dates quoted in the text should be grouped in form of single table or supplement separated from the main text and quoted according to the presented conventional standard form. The list of TL dates should be accomplished with the reference to recent relevant paper containing detailed description of methods used to obtain the TL dates and appropriate figure showing an example of the family of TL glow curves. Moreover, each of the TL dates should be preceded with short name of dated sample with appropriate short genetical definition of the type of sediment, and, eventually, depth of the sample below actual level of the ground.