Optically stimulated luminescence

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].

Research Spending & Results

Luminescence dating refers to a group of methods of determining how long ago mineral grains were last exposed to sunlight or sufficient heating. It is useful to geologists and archaeologists who want to know when such an event occurred. It uses various methods to stimulate and measure luminescence. All sediments and soils contain trace amounts of radioactive isotopes of elements such as potassium , uranium , thorium , and rubidium.

These slowly decay over time and the ionizing radiation they produce is absorbed by mineral grains in the sediments such as quartz and potassium feldspar. The radiation causes charge to remain within the grains in structurally unstable “electron traps”.

Optically stimulated luminescence (OSL) dating or optical dating provides a measure of This residual level is the point from which the geological OSL signal.

Skip to main content Skip to table of contents. This service is more advanced with JavaScript available. Encyclopedia of Earthquake Engineering Edition. Contents Search. Luminescence Dating in Paleoseismology. Reference work entry First Online: 11 October How to cite. Optically stimulated luminescence OSL dating or optical dating provides a measure of time since sediment grains were deposited and shielded from further light or heat exposure, which often effectively resets the luminescence signal Fig.

Testing Luminescence Dating Methods for Small Samples from Very Young Fluvial Deposits

The last 2. To be able to fully understand and interpret past climate variations the development of accurate and precise chronological techniques is crucial. Optically stimulated luminescence OSL dating is a strong geochronological tool that can be used to date across a wide time range, from the modern days to a few hundred thousand years ago. It has been used to date sediments in nearly all parts of the world.

optically stimulated luminescence (OSL) dating tech- developing a geological and climatic history of Mars OSL Dating Principles: Luminescence dating is.

Optically-Stimulated Luminescence is a late Quaternary dating technique used to date the last time quartz sediment was exposed to light. As sediment is transported by wind, water, or ice, it is exposed to sunlight and zeroed of any previous luminescence signal. Once this sediment is deposited and subsequently buried, it is removed from light and is exposed to low levels of natural radiation in the surrounding sediment. Through geologic time, quartz minerals accumulate a luminescence signal as ionizing radiation excites electrons within parent nuclei in the crystal lattice.

A certain percent of the freed electrons become trapped in defects or holes in the crystal lattice of the quartz sand grain referred to as luminescent centers and accumulate over time Aitken, In our laboratory, these sediments are exposed to an external stimulus blue-green light and the trapped electrons are released. The released electrons emit a photon of light upon recombination at a similar site.

In order to relate the luminescence given off by the sample to an age, we first need to obtain the dose equivalent to the burial dose. Following the single-aliquot regenerative SAR method of Murray and Wintle , the dose equivalent De is calculated by first measuring the natural luminescence of a sample. Then, the bleached sample is given known laboratory doses of radiation, referred to as regenerative doses. The regenerative dose data are fit with a saturating exponential to generate a luminescence dose-response curve.

The De is calculated by the intercept of the natural luminescence signal with the generated curve. A curve is generated for each aliquot subsample , multiple aliquots are needed to obtain an accurate De.

References

Luminescence dating is a geochronological technique that spans the Late Quaternary. It is particularly useful for minerogenic sediments, for example as optically stimulated luminescence OSL dating of quartz and infrared stimulated luminescence IRSL dating of feldspar. Thermoluminescence TL dating can also be used to determine the age of pottery.

The Lund Luminescence Laboratory was established in , as the first of its kind in Sweden.

Optically Stimulated Luminescence dating is a technique of dating Late Quaternary sediments deposited by various transporting agencies after their erosion.

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. Analysis of fully bleached samples is preferred as this ensures that associated errors are kept to a minimum. Despite this, procedures exist with which to identify and take account of partially bleached grains, as may be seen in fluvial, or more likely glacial sediments, where light exposure may have been attenuated by turbid or turbulent conditions.

It is important to observe certain conventions when collecting samples in order to reduce errors as much as possible.

Luminescence dating

Over the last 60 years, luminescence dating has developed into a robust chronometer for applications in earth sciences and archaeology. The technique is particularly useful for dating materials ranging in age from a few decades to around ,—, years. In this chapter, following a brief outline of the historical development of the dating method, basic principles behind the technique are discussed.

The luminescence dating laboratory dates clastic sediments of Middle and Late Quaternary ages. The lab is equipped with two TL/OSL Riso readers, one with.

In physics , optically stimulated luminescence OSL is a method for measuring doses from ionizing radiation. It is used in at least two applications:. The method makes use of electrons trapped between the valence and conduction bands in the crystalline structure of certain minerals most commonly quartz and feldspar. The ionizing radiation produces electron-hole pairs: Electrons are in the conduction band and holes in the valence band.

The electrons that have been excited to the conduction band may become entrapped in the electron or hole traps. Under the stimulation of light, the electrons may free themselves from the trap and get into the conduction band.

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.

Once the sand grain has been buried and it is no longer exposed to sunlight, the OSL signal starts to accumulate.

Calculating Age | Challenges for OSL | Case studies of OSL dating in to determine how long rocks, for example, have been exposed on the.

Beach ridges that form during seaward migration of a shoreline indicate the successive positions of past shorelines; their age and distribution can therefore provide a geological record of past coastal changes Tamura, Because beach-ridge deposits generally lack material suitable for radiocarbon dating e. The Yumigahama Peninsula is a sandy coastal barrier with a well-developed sequence of beach ridges Sadakata, An immense increase in sediment discharge from the catchment of the neighboring Hino River in response to 17 th and 18 th century mining of iron for the manufacture of swords Sadakata, ; Tokuyasu, enhanced sediment deposition that caused rapid seaward migration of the shoreline and the development of a sequence of ridges.

Absolute dating of the ridge sediments will help to quantify the effect of human activity on the geomorphology of this region. Although optically stimulated luminescence OSL of quartz grains has generally been the first choice for dating Holocene coastal deposits, problems related to the OSL properties of quartz have been reported from many regions of Japan e.

The use of post-infrared post-IR infrared stimulated luminescence IRSL of K-feldspar at relatively low temperatures Thomsen et al , ; Reimann et al , b has reduced the undesirable effects of both anomalous fading and residual dose and has provided a robust method of dating Holocene sediments e. It is a sandy coastal barrier that is 20 km long and 2. The Hino River flows into the Japan Sea at the southeastern end of the barrier, and most of the sand discharged at the river mouth is transported northwest along the shore by dominantly northeasterly waves Sato et al ,

DRI Luminescence Laboratory

Up to now not a single dating technique has been developed for in-situ planetary exploration. The only information on the age of extraterrestrial planetary surfaces comes from the “crater-counting” method. This method has an inherent large error and low resolution and is completely inadequate for local geology. Luminescence dating has possibly the potential to open up a completely new discipline in planetary in-situ exploration.

This assessment has a strategic value for the development of a new generation of in-situ instrumentation.

Luminescence dating of geological and archaeological objects. Summary. Absolute dating by luminescence methods is widely applicable in geology.

Jack Rink about a new technique that he using to determine the age of the Crystal River archaeological site. He began his education in Florida where he received his Ph. After working on projects in Africa, Europe and Asia, Dr. Rink returned to Florida several years ago to work on the Salt Springs site near Palatka. He has since worked at sites around the state including several shell middens on St. Rink and his associates specialize in a special type of geochronology called Optical Stimulated Luminescence—or OSL for short—that is used to date archaeological sites and geological features.

OSL dating is a system of sampling and measuring the amount of energy that is trapped within soils. Quartz and quartzite accumulate energy in them through time. The rate of breakdown and energy release is relatively constant.

Luminescence Dating: Applications in Earth Sciences and Archaeology

D granting institution. The OSL lab at NMHU will support research that will benefit from the ability to date the burial ages of silicate phases in geological and archaeological materials up to several hundreds of thousands years before present. The instrument will support Quaternary investigations of the timing and extent of past glaciations and subsequent retreat and the influence of past climate on plant and animal life and human evolution and distribution. The OSL lab will be the first of its kind in the state of New Mexico and will support experiential laboratory training for a student population dominated by Hispanic students.

Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content. It has applications in variety of fields which include medicine, national security, geology, archeology and environmental studies.

OSL dating is based on the ability of minerals to store energy (Preusser over geological times scales, depending on the environment and the.

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.

Similarly, inaccurate estimates of pore water salinity will dramatically affect the results. Price The limiting factor in the age range for luminescence dating is the ‘saturation’ of the signal at large price rates i. Accurate age determination therefore becomes increasingly difficult for older samples and there is a loss in dating precision an increase in central uncertainty.

The point at which a sample becomes saturated depends on the holiday rate of the sample. Samples subjected to a high dose rate will become stimulated more quickly, and fully saturated samples will optically record the full duration of their luminescence history. In these cases only a minimum age can be determined. However, it is possible to identify saturated samples through measurement.

Luminescence Dating in Paleoseismology

Please reference: Mallinson, D. Optically stimulated luminescence is a method of determining the age of burial of quartz or feldspar bearing sediments based upon principles of radiation and excitation within crystal lattices, and stems from the fact that imperfections in a crystal lattice have the ability to store ionizing energy Aitken , ; Botter -Jensen et al.

Radiation within sediments comes from alpha, beta, and gamma radiation emitted during the decay of U, U, Th, 40 K, and 87 Rb, and their daughter products, both within the mineral grains and in their surroundings Lian , , and from cosmic rays Figure 1. Under controlled laboratory conditions, assuming the sample was collected under light-restricted conditions, controlled exposure of the sample to photons yields a luminescence response the equivalent dose, D e , the intensity of which is a function of the dose rate within the sediment, and the length of time the sample was exposed to the background radiation.

In order to measure the age, two factors must be known; 1 the environmental dose rate, and 2 the laboratory dose of radiation that produces the same intensity of luminescence as did the environmental radiation dose the equivalent dose.

In this paper, we confirm that quartz OSL dating is unsuitable for (B) Simplified geological map of the Hino River catchment (after Inoue et al.

This indicates that fine-grained sediments in the Mekong River Cambodia are sufficiently bleached at deposition and can yield reliable quartz OSL ages for establishing the chronology of the floodplain. The sufficient bleaching of fine-grained quartz partly results from the long transport distance and may also occur in other large river systems. Precise and accurate dating of fluvial deposits is essential to understand floodplain evolution during the Holocene.

Although radiocarbon dating has been commonly used to reconstruct floodplain evolution Aslan and Autin, ; Berendsen and Stouthamer, ; Funabiki et al. In contrast, optically stimulated luminescence OSL can be applied directly to quartz and feldspar grains, the main components of fluvial deposits, and provides an alternative way for establishing floodplain chronology. Previous studies have successfully applied OSL dating to fluvial deposits, although the luminescence signals of water-lain sediments are often incompletely zeroed prior to deposition due to the limited exposure to sunlight Rittenour et al.

Quartz sand grains are generally used for the OSL dating of fluvial deposits because 1 incomplete bleaching can be detected from the dose distribution of small aliquots or single grains Wallinga, , and 2 coarser grains are better bleached in many cases, possibly because of longer residence time on the riverbed and sunlight exposure on channel bars Olley et al. Furthermore, accurate ages can be obtained in combination with statistical methods such as minimum age model MMA; Galbraith et al.

Hu et al. Shen and Mauz reported that the fine-grained quartz has small residual doses equivalent to ca. Chamberlain et al.

50) Geologic Dating Methods


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