This paper aims to provide an overview concerning the optically stimulated luminescence OSL dating method and its applications for geomorphological research in France. An outline of the general physical principles of luminescence dating is given. A case study of fluvial sands from the lower terrace of the Moselle valley is then presented to describe the range of field and laboratory procedures required for successful luminescence dating. The paper also reviews the place of OSL dating in geomorphological research in France and assesses its potential for further research, by focusing on the diversity of sedimentary environments and topics to which it can be usefully applied. Hence it underlines the increasing importance of the method to geomorphological research, especially by contributing to the development of quantitative geomorphology. They are now largely used to date not only palaeontological or organic remains, but also minerals that characterise detrital clastic sedimentary material. The most common methods applied to minerals are cosmogenic radionuclides, electron spin resonance ESR and luminescence techniques. The latter were first applied to burned minerals from archaeological artefacts [thermoluminescence TL method]. Improvements of this technique led to the development, for more than twenty years, of the optical dating method [commonly referred to as Optically Stimuled Luminescence OSL ] which is now applied to sediments from various origins Wintle,
Optically Stimulated Luminescence
Introduction How do we measure the OSL signal? How do we measure the radiation dose rate? Another way of dating glacial landforms is optically stimulated luminescence dating OSL. OSL is used on glacial landforms that contain sand, such as sandur or sediments in glacial streams. The OSL signal is reset by exposure to sunlight, so the signal is reset to zero while the sand is being transported such as in a glacial meltwater stream.
Principles of Luminescence Dating. Optically stimulated luminescence was developed.
Luminescence dating, particularly using optically stimulated luminescence OSL , is revolutionizing Quaternary and archaeological science because it allows dating of sediments and artifacts that perhaps 10 years ago could not be dated. The lab has produced more than OSL ages from years to , years for aeolian, fluvial, lacustrine, and marine sediments, as well as pottery, artifacts and secondary carbonate.
Chronologies have been developed for archaeological sites in Botswana and the U. As the OSL of a sediment is quickly lost when exposed to sunlight tens of seconds many sediments are bleached lack an OSL signal when deposited and buried. After deposition these sediments accumulate luminescence which can be measured allowing the age of burial to be determined.
There is now convincing evidence that many glacial, fluvial, aeolian, and even shallow marine sediments can be dated by OSL techniques. The upper limit of age by OSL is largely determined by the annual dose on the sediment which is related to it’s content of uranium, thorium and potassium. Low levels of radioactive isotopes in the sediment lead to very slow saturation of quartz and feldspar grains by released electrons and so ages in excess of ka may be possible.
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Resources home v2. Introduction Services Prices. Application Central for samples up to about Lund containing quartz. Technical Geography Laboratory All sediments contain trace minerals including uranium, thorium and potassium. Water Content Calibration Water within the soil has an attenuating effect on the ambient radiation. Consequently, samples analysed without price of their water content or using a low estimate of water content will return ages younger than samples corrected for this luminescence.
Abstract: Optically stimulated luminescence (OSL) dating of light-exposed sediments is used increasingly as a mean of establishing a sediment deposition.
The OSL optically stimulated luminescence dating method exploits dosimetric properties of grains of minerals naturally occurring in sediments and man-made materials. In archaeology the OSL method is used to date pottery and other heated materials e. When compared with the radiocarbon method it makes possible dating objects containing no organic matter or originating in periods for which the radiocarbon method is less accurate due to the shape or lack of the calibration curve.
The principles of Luminescence Dating
The possible role of environmental change, especially sea level change, as a stimulus for the development of human residence and migration is poorly understood. We investigate this problem by showing a record of sea-level change and coastal transformation based on a sediment core FN1 core and a Neolithic site Pingfengshan site obtained from the Funing bay on the northeast coast of Fujian, China.
Samples from FN1 core and Pingfengshan site were taken for grain size ananlyses and for optically stimulated luminescence OSL dating.
Optically Stimulated Luminescence. OSL dating involves measurement of electron accumulation in light-sensitive traps in minerals such as quartz, zircon.
Portable Spectrofluorimeter for non-invasive analysis of cultural heritage artworks using LED sources. Luminescence spectroscopy – Spatially resolved luminescence – Time resolved luminescence – Electron spin resonance ESR. Flint and heated rocks – Ceramics and pottery – Unheated rock surfaces – Tooth enamel and quartz grains – Sediment dating. LexEva is a newly released evaluation software developed for analysis in luminescence research and dating.
Few years depending on signal intensity and sensitivity of equipment for which the lexsyg systems are especially developed. Radiation Measurements 32,
Luminescence Dating: Applications in Earth Sciences and Archaeology
Jain Mayank, Murray A. Optically stimulated luminescence dating: how significant is incomplete light exposure in fluvial environments? In: Quaternaire , vol.
Oslo. ISSN Optically Stimulated Luminescence (OSL) dating allows age determinatio n of sediments deposited during the last glacial–interglacial cycle.
We are applying here the current state of the art luminescence dating protocols for revisiting the chronology of this section. Laboratory generated SAR dose response curves in the high dose range 5 kGy for fine quartz and 2 kGy for coarse quartz were investigated by employing a test dose of either 17 or Gy. The results confirm the previously reported different saturation characteristics of the two quartz fractions, with no evident dependency of the equivalent dose D e on the size of the test dose.
The previous reports regarding the chronological discrepancy between the two quartz fractions are confirmed. However, while previous investigations on other sites concluded that this discrepancy appears only above equivalent doses of about Gy, here fine grain quartz ages underestimate coarse quartz ages starting with equivalent doses as low as around 50 Gy.
The development of the single-aliquot regenerative-dose SAR protocol [ 1 ] for optically stimulated luminescence OSL dating of quartz has revolutionized the luminescence dating method by giving rise to high precision equivalent dose estimates. Loess-paleosol sequences are important archives of the climatic changes that took place during the Pleistocene, but their significance can only be fully understood once a reliable and absolute chronology is available.
Due to its quartz rich and windblown nature, loess is generally considered an ideal material for the application of OSL. However, although more precise ages can be obtained by SAR-OSL, the validation of the accuracy of these OSL ages by independent age control is hindered by the lack of methods which can directly date the depositional time of the sediments.
However, it is well known that the results of luminescence dating methods applied on quartz underestimate the expected ages for samples collected below this soil.
Optical : Relating to the use of visible or near-visible light. Stimulated : To excite with a stimulus light or heat. Optically stimulated luminescence : The emission of light from crystalline materials when stimulated by light following previous absorption of energy from radiation. Luminescence dating consists of a family of analytical methods, most of which are used in archaeological research.
They can be applied to samples ranging in age from just a few years to several hundreds of thousands of years beyond the range of radiocarbon dating , and they are, therefore, able to cover a time interval that includes important turning points in the evolution of humans. The choice of luminescence method depends on the availability of appropriate minerals, the time period of interest, and the nature of the target event.
Optically stimulated luminescence (OSL) dating has become one of the foremost techniques in establishing this framework. OSL is based on the.
Luminescence dating is used to identify when a sample was last exposed to daylight or extreme heat by estimating the amount of ionising radiation absorbed since burial or firing. This equation very simply expresses the calculations necessary, but it is important to be aware of the factors influencing the two values used. Heterogeneous sediments and radioactive disequilibria will increase errors on Dr, while incomplete bleaching of the sample prior to burial, anomalous fading in feldspars, and the estimation of past sediment moisture content may all also add to increased errors.
The dating of sediments using the luminescence signal generated by optical stimulation OSL offers an independent dating tool, and is used most often on the commonly occurring minerals of quartz and feldspar and, as such, has proved particularly useful in situations devoid of the organic component used in radiocarbon dating. Quartz has been used for dating to at least ka, while the deeper traps of feldspar have produced dates as old as 1 ma.
The use of fine-grain dating for samples such as pottery, loess, burnt flint and lacustrine sediments, and coarse-grain dating of aeolian, fluvial and glacial sediments is regularly undertaken. While thermoluminescence TL, the generation of a luminescence signal generated by thermal stimulation is still conducted on pottery and burnt flint samples, the bulk of luminescence dating now uses optical stimulation as this releases a signal that is far more readily zeroed than that re-set by heat.