Luminescence dating is a rapidly expanding field. Recent advances in methodology and instrumentation have improved both its accuracy and precision, such that it is now becoming an important player in Quaternary science. The advantage luminescence has over other techniques is the ability to date directly events of archaeological and geological interest: the last heating of ceramics and lithics and the last exposure of light for sediments. This often eliminates the need to establish a linkage between the dating event and the target event and thereby the loss of accuracy associated with such bridging arguments. Luminescence is not as precise as some dating methods, but errors between 5 and 10 percent are commonly obtained. Go in About Luminescence Dating. Luminescence is the emission of light from crystalline materials following the absorption of energy from an external source.
Alastair C. We have attempted to isolate the fast component of the quartz optically stimulated luminescence OSL signal using a curve-fitting procedure. By pre-determining the decay constants, the procedure is simple enough to be scripted, allowing a large number of aliquots to be processed. A Monte Carlo error routine is used, in which simulated decay curves are fitted with several exponentials, which vary in their decay rates according to the measured distributions of fast and medium component decay rates.
However, there have been relatively few tests of the accuracy of quartz OSL dating beyond this age range. It should, in principle, be possible to use quartz to.
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.
By taking samples from well-sorted sediment structures problems with heterogeneous dose rates may be avoided, and all grains are more likely to have undergone the same depositional history. Any areas of disturbance such as soil formation, groundwater leaching, bioturbation or slumping, should be avoided to remove the potential for post-depositional mixing of grains. As the exclusion of light exposure is vital, opaque steel or plastic tubes are driven into sediment taking care to discard any material that may have undergone exposure.
All subsequent preparation is conducted under subdued orange light to avoid the early stimulation of any trapped charge.
OSL Dating in Archaeology
Jain Mayank, Murray A. Optically stimulated luminescence dating: how significant is incomplete light exposure in fluvial environments? In: Quaternaire , vol. Fluvial Archives Group. Clermond-Ferrant Optically stimulated luminescence OSL dating of fluvial sediments is widely used in the interpretation of fluvial response to various allogenic forcing mechanisms during the last glacial-mterglacial cycle.
natural minerals; optically stimulated luminescence (OSL) dating of sand-sized quartz grains is the most reliable and most widely used method (e.g. Wintle.
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.
Advertisement Hide. Conference paper. This is a preview of subscription content, log in to check access. Aitken M. Introduction to optical dating: the dating of Quaternary sediments by the use of photon-stimulated luminescence. Oxford: Oxford University Press,
Optically stimulated luminescence and isothermal thermoluminescence dating of high sensitivity and well bleached quartz from Brazilian sediments: from Late Holocene to beyond the Quaternary? E-mail: andreos usp. E-mail: ligia. E-mail: ccfguedes gmail. E-mail: wsallu gmail.
Luminescence dating is used to identify when a sample was last exposed to Figure 1 Illustration of the accumulation of an OSL signal while a sample is buried, and it is possible to produce ages with an accuracy of between 5 and 12%.
This paper presents a preliminary study on lake-level fluctuations since the Last Glaciation in Selin Co lake , Central Tibet, by dating four groups of beach ridges using optically stimulated luminescence OSL. This date further supports that no plateau-scale ice sheet covered the Tibetan Plateau during the Last Glaciation. The other three groups produce OSL ages of On the plateau scale, these four beach ridge groups are almost synchronous with advances or standstills of Himalayan glaciers, indicating similar climate controls across the central and southern Tibetan Plateau, and being consistent with the conclusion, obtained from nearby ice core records, that this area is affected by the South Asia monsoon.
Furthermore, beach ridges are also synchronous with fluvial terraces in the northern Tibetan Plateau, implying common driving forces during their formation. Therefore, some terraces may be formed as a result of climate events rather than being of tectonic origin. Contents 1. Introduction 2. Study area 3. Material and method 3. Field work 3. Laboratory analysis 4. Results and discussions 4. OSL ages of beach ridges 4.
Optically stimulated luminescence dating of young quartz using the fast component
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.
Luminescence Dating. Guidelines on luminescence dating methods in archaeology. The guidelines the issues that may affect the reliability of luminescence ages OSL optically stimulated luminescence. P palaeodose, another term used.
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.
Luminescence Dating: Applications in Earth Sciences and Archaeology
The Luminescence Dating and Dosimetry Laboratory is developing new techniques for application to the dating of artefacts and deposits from sites that range widely in terms of chronological period, geographic location and material type. Recent work as focused on optically stimulated luminescence OSL techniques, in particular a novel experimental approach to the measurement of single grain OSL. A study produced, for the first time, absolute dates for a range of brick stupas located within the hinterland of Anuradhapura , contributing to the further development of a brick monument chronology for the region.
This method has an inherent large error and low resolution and is completely inadequate for local geology. Luminescence dating has possibly.
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.
This is followed by a look at measurement equipment that is employed in determining age and its operation. Luminescence properties of minerals used in dating are then examined after which procedures used in age calculation are looked at. Sample collection methods are also reviewed, as well as types of materials that can be dated. Continuing refinements in both methodology and equipment promise to yield luminescence chronologies with improved accuracy and extended dating range in the future and these are briefly discussed.
Luminescence – An Outlook on the Phenomena and their Applications. Luminescence dating refers to age-dating methods that employ the phenomenon of luminescence to determine the amount of time that has elapsed since the occurrence of a given event. In this chapter, the application of luminescence techniques in dating geological and archaeological events is examined. Generally, the term luminescence dating is a collective reference to numerical age-dating methods that include thermoluminescence TL and optically stimulated luminescence OSL dating techniques.
Other terms used to describe OSL include optical dating [ 1 ] and photon-stimulated luminescence dating or photoluminescence dating [ 2 ].
The principles of Luminescence Dating
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.
OSL dating of fine-grained fluvial deposits may have an underutilised potential for establishing an accurate chronology of mud-dominated.
Williams, A. Journal of Archaeological Science: Reports, Here we present the results of a multi-phase compliance-based archaeological excavations of a new bridge crossing the Hawkesbury-Nepean River northwest Sydney. These works identified a Last Glacial Maximum LGM aeolian deposit through which a colonial era drainage system had been excavated. Historical documents reveal the construction of the system occurred between and CE. An opportunistic range-finding Optically Stimulated Luminescence OSL sample was obtained from anthropogenic trench backfill — composed of reworked LGM deposits — immediately above the drainage system.
Optically Stimulated Luminescence
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.
Joel Q. Optically stimulated luminescence dating of young sediments and dusts. N2 – In many geological and archaeological studies investigated within a Late Quaternary timeframe, one or more of a suite of different optically stimulated luminescence OSL approaches may now be applied to provide critical chronological constraint. Such luminescence applications might be in instances where age exceeds radiocarbon limits or there is a paucity of organic material.
Accurate luminescence geochronology of very young 10s to s yr timeframe deposits is also achievable, provided that certain luminescence characteristics and depositional environment factors hold true. Important considerations are: sufficiently high specific luminescence sensitivity to enable measurement of very small doses; whether thermal transfer signals lead to dose overestimation; a more familiar problem of extent of optical resetting; and, whether the dose-rate is accurately reconstructed for shallow-depth surficial deposits with changing depositional environment.
Data from studies over the last few years will be used to illustrate the challenges of OSL dating of very young sediments, including recent work on attic dust deposits and the specific problems of dose-rate reconstruction for very thin nearly equal 5 mm layers. AB – In many geological and archaeological studies investigated within a Late Quaternary timeframe, one or more of a suite of different optically stimulated luminescence OSL approaches may now be applied to provide critical chronological constraint.
Illinois State Geological Survey. Overview Fingerprint. Abstract In many geological and archaeological studies investigated within a Late Quaternary timeframe, one or more of a suite of different optically stimulated luminescence OSL approaches may now be applied to provide critical chronological constraint.