Optically stimulated luminescence dating of fluvial deposits
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.
Optically stimulated luminescence
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 stimulation of light the electrons may free themselves from the trap and get into the conduction band. From the conduction band they may recombine with holes trapped in hole traps.
If the centre with the hole is a luminescence center radiative recombination centre emission of light will occur. The photons are detected using a photomultiplier tube. The signal from the tube is then used to calculate the dose that the material had absorbed. The OSL dosimeter provides a new degree of sensitivity by giving an accurate reading as low as 1 mrem for x-ray and gamma ray photons with energies ranging from 5 keV to greater than 40 MeV.
The OSL dosimeter's maximum equivalent dose measurement for x-ray and gamma ray photons is rem. For beta particles with energies from keV to in excess of 10 MeV, dose measurement ranges from 10 mrem to rem. Neutron radiation with energies of 40 keV to greater than 35 MeV has a dose measurement range from 20 mrem to 25 rem. In diagnostic imaging the increased sensitivity of the OSL dosimeter makes it ideal for monitoring employees working in low-radiation environments and for pregnant workers.
To carry out OSL dating, mineral grains have to be extracted from the sample. Occasionally other grain sizes are used. The difference between radiocarbon dating and OSL is that the former is used to date organic materials, while the latter is used to date minerals. Events that can be dated using OSL are, for example, the mineral's last exposure to sunlight; Mungo Man , Australia's oldest human find, was dated in this manner. In archaeology, OSL dating is applied to ceramics: Recent OSL dating of stone tools in Arabia pushed the "out-of-Africa" date hypothesis of human migration back 50, years and added a possible path of migration from the African continent to the Arabian peninsula instead of through Europe.
From Wikipedia, the free encyclopedia. Method of measuring radiation doses, often used in mineral dating. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: Annual Review of Earth and Planetary Sciences. Financial Times requires registration. Archived from the original on January 3, Murray, A.
Luminescence dating of quartz using an improved single-aliquot regenerative-dose protocol. Radiation Measurements Vol. Retrieved from " https: Particle detectors Dating methodologies in archaeology. Hidden categories: Articles with short description Articles needing additional references from March All articles needing additional references All articles with unsourced statements Articles with unsourced statements from March Namespaces Article Talk.
Recent advances in OSL techniques and the development of single-grain dating capabilities have now allowed fluvial deposits, and other. Optically Stimulated Luminescence (OSL) dating allows age determination of sediments deposited during the last glacial‐interglacial cycle.
During the penultimate glaciation vast areas of the Alps were glaciated, with piedmont glaciers protruding into the foreland. In the easternmost part of the northward draining valleys of the Alps, the glaciers did not reach the foreland, but formed valley glaciers confined by the mountainous terrain. This also applies to the Ybbs valley, where samples for luminescence dating out of glaciofluvial gravel accumulations were taken at three locations along the present day river course. In a highly dynamic depositional environment, such as a glacier-fed river system, incomplete resetting of the luminescence signal is possible, in particular when transport distances are short. Because previous research has shown, and as corroborated within this study, quartz from the research area exhibits analytical problems in the high age range.
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Soares I ; Sonia H. Rodrigo O.
Optically stimulated Luminescence dating of quartz
The full text of this article hosted at iucr. Use the link below to share a full-text version of this article with your friends and colleagues. Learn more. This relatively new technique therefore enables chronological frameworks to be established for fluvial deposits that often cannot be dated by other means. The OSL signal of quartz and feldspar minerals is reset by light exposure during fluvial transport, and builds up as a result of ionizing radiation after burial of the minerals. Incomplete resetting of the OSL signal because of inadequate light exposure in the fluvial environment can result in age overestimations, especially for relatively young samples. Methods used for the detection of incomplete resetting, or poor bleaching, are reviewed. It is argued that technique s measuring the OSL signal from small subsamples aliquots are most promising for detecting poor bleaching and for obtaining the true age for a sample in which not all grains had their OSL signal completely removed at deposition. Quartz should be the mineral of choice, because it has been shown to yield the most reliable results and because its OSL signal is more rapidly reset than that of feldspar.
This paper aims to provide an overview concerning the optically stimulated luminescence OSL dating method and its applications for geomorphological research in France.
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The full text of this article hosted at iucr. Tammy M. Use the link below to share a full-text version of this article with your friends and colleagues. Learn more. Fluvial deposits and landforms are important archives of river response to climate, tectonics and base level change and are commonly associated with archaeological sites. Unlike radiocarbon dating, the target material for optically stimulated luminescence OSL dating sands and silts is nearly ubiquitous in fluvial deposits and the age range for OSL spans the last glacial—interglacial cycle, a time period of interest to many Quaternary scientists. The application of OSL dating to fluvial deposits is discussed with respect to its potential to provide important contributions to research in the fields of geomorphology, palaeoseismology and archaeology. Examples are given from each research field. Volume 37 , Issue 4. Please check your email for instructions on resetting your password. If you do not receive an email within 10 minutes, your email address may not be registered, and you may need to create a new Wiley Online Library account. If the address matches an existing account you will receive an email with instructions to retrieve your username.
Toggle navigation ScienceBase-Catalog. Your browser does not have support for cookies enabled. Some features of this application will not work. Tammy M Rittenhour, Luminescence dating of fluvial deposits: Summary Fluvial deposits and landforms are important archives of river response to climate, tectonics and base level change and are commonly associated with archaeological sites.
.optically stimulated luminescence