Quaternary TL Surveys

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Quaternary TL Surveys was set up in 1993 as an independent commercial laboratory providing thermoluminescence (TL) date measurement services to archaeologists and geologists. The range of services available includes applications to flint, stone and stalagmitic calcite from the Middle Pleistocene onwards, and to Upper Pleistocene and Holocene sediments.



UNIQUE QUALITIES OF THERMOLUMINESCENCE - a description of the special features of TL, and of the additional information that can be gathered from them. The various ways in which this information may be used to refine the date measurement are illustrated with examples from the dating of sediments.




THE DATING OF NEANDERTHAL SITES - extracts from a talk given at the symposium "Neanderthals in Europe" held in the Gallo-Roman Museum in Tongeren, Belgium, 17th - 19th September 2004.




A GUIDE TO TL DATE MEASUREMENT

An important function of the company is to make available information about the TL method and thereby help date users to take the best advantage of what it has to offer. In fact, the TL date measurement consists of two distinct measurements. The first measurement involves TL examination of the sample, and results in an evaluation of the quantity of natural radiation to which it has been exposed. In the second measurement, data is collected on natural radiation levels both within and around the sample, and from these an assessment is made of the rate at which the radiation dose was received. By combining these two measurements, the length of time over which the radiation exposure occurred can then be calculated.

The assessment of the dose-rate is often the most demanding part of the dating procedure. It usually involves a measurement of radiation levels in the burial environment of the sample. Thus, TL date measurement may be impossible (or, at least, very difficult) if the site from which the sample derived is destroyed or made inaccessible. For this reason, date users should be prepared to anticipate their requirements for TL dates. In many circumstances, the best time to consider TL dating is before or during fieldwork, rather than at the post-excavation stage.

The precision of the TL date measurement is usually determined by the degree of uncertainty in the dose-rate assessment. This, in turn, often depends on environmental factors at the site and on the range of possible past conditions that these may have undergone. Because of this, working procedures have been developed to allow a feasibility study to be carried out in advance of any decision to commission date measurements. In many cases, the feasibility study will involve an examination of the site. The purpose of the study is to provide the date user with an estimate of the likely precision that will be achievable in the proposed date measurements. The date user will also be offered a minimum specification for dating precision which will regulate the price charged for the information. Date users may choose to dispense with the feasibility study (e.g. when the site is similar to ones previously dated) but, in general, are advised to take advantage of this procedure.

The following guidance notes are intended to provide the date user with the necessary information to get the best results from TL date measurements. The sections are marked by ** contain important information; those that are marked with * contain useful information; while the rest are made available as background information. For the purposes of printing hard copy, each chapter of the guide is a separate document.



A GUIDE TO TL DATE MEASUREMENT - Contents




Queries and comments on TL dating procedures and the above literature are welcome.

E-mail n.debenham@qtls.globalnet.co.uk
or Telephone/Fax Nick Debenham +44 (0)115 985 6785


Quaternary TL Surveys