Optically stimulated luminescence dating of rock surfaces. N2 – There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence OSL dating is a well-established chronological tool that has successfully determined the depositional age of a wide variety of fine-grained sediments, from several years to several hundred thousands of years. However, there is no routine OSL dating method applicable to larger clasts such as cobbles, boulders and other rock surfaces. Here the application of quartz OSL to the dating of rock surfaces is successfully tested by application to two different quartz-rich rock types sandstone and quartzite. Together with the measurement of infrared stimulated luminescence IRSL signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can be fully reset in the two mm closest to the rock surface. However, it appears that the sensitivity of quartz from the granitic rocks the most common surficial rock type cannot be relied on. Na-rich feldspar is suggested as an alternative dosimeter, using a yellow-emission elevated-temperature IRSL signal. Based on the studies of residual luminescence as a function of depth into a rock surface discussed above, a model is developed that relates this increase in residual luminescence to the exposure time. The model is then further developed using the quartz OSL signal from buried quartzite cobbles to include the effects of the environmental dose rate.
Testing Luminescence Dating Methods for Small Samples from Very Young Fluvial Deposits
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.
In physics, optically stimulated luminescence (OSL) is a method for measuring doses from ionizing radiation. It is used in at least two applications: Luminescence dating of ancient materials: mainly geological sediments and.
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.
Optically Stimulated Luminescence OSL dating has emerged within the last 20 years as a key Quaternary absolute dating tool, with a wide range of terrestrial and marine applications. Optical dating techniques employ ubiquitous quartz or feldspar grains to directly date the deposition of sedimentary units. As such, the optical dating methods allow the systematic chronological evaluation of Quaternary-age sedimentary sequences.
Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully determined the depositional age of a wide variety.
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.
Luminescence Dating: Applications in Earth Sciences and Archaeology
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.
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.
Email Address. Sign In. Holocene right-slip rate determined by cosmogenic and OSL dating on the Anar fault, Central Iran Abstract: 10 Be cosmic ray exposure CRE and optically stimulated luminescence OSL dating of cumulative offset of alluvial fan surfaces have been performed to derive the long-term slip-rate of the Anar fault. At two sites, the comparison between OSL ages obtained within the latest sediments emplaced during the aggradation of the fan and cosmogenic exposure ages of the pebbles abandoned on the surface before its incision and subsequent dextral offset indicates a significant and variable CRE inheritance.
The latest regional incision in the Anar area appears rather coeval with the onset of the early-middle Holocene pluvial episode 6— Article :. Date of Publication: Nov.
Optically stimulated Luminescence dating of quartz
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 time since sediment grains were deposited and shielded from further.
Optically stimulated luminescence OSL dating has proven to be extremely useful for establishing the Late Quaternary chronological framework in many areas of the Brazilian territory. In this region dominated by tropical climate, OSL dating can be more extensively applied than radiocarbon dating due to the generally low potential for the preservation of organic matter in sedimentary samples. This problem is especially critical in areas of the Amazonian lowlands, because of the hot climate and high precipitation rates.
The abundance of quartz grains deposited in fluvial and aeolian environments over this region favours OSL dating. More than 20 years of continuous and collaborative work has resulted in the creation of an extensive OSL age database for Late Quaternary sedimentary deposits in the Amazonian lowlands. This effort has contributed to improving the paleoenvironmental and paleoclimatic reconstructions of this region within this period.
This book discusses the state of art of OSL dating of Late Quaternary deposits in the Amazonian lowlands, focusing on providing an introduction to dating principles using OSL, and defining the application of OSL techniques as a dating method. It also offers a statistical study and calculation of equivalent dose and annual dose rates, details the sampling and experimental apparatus, and considers the difficulties and adaptation techniques in dating Late Quaternary strata in the Amazonian lowlands.
Her research interests lie in the area of OSL and the thermoluminescence TL of crystals applied to geochronology and environmental ionizing radiation dosimetry. She has published more than 80 peer-reviewed journal articles and conference proceedings and is a referee for 16 international journals. Her research focuses on geomorphologic, stratigraphic and sedimentologic analyses of Amazonian basins, as well as basins of the Equatorial South Atlantic Brazilian Margin. She has published peer-reviewed journal articles and 20 book chapters, and has presented her work at numerous meetings and conferences.
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.
The ISGS OSL dating lab is equipped with a Risø TL/OSL-DA Reader; Gamma Spectrometers; two amber light prep labs with fume hoods, shatter box.
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. OSL works because all sediments have some natural radioactivity, caused by the presence of uranium, thorium and potassium isotopes in heavy minerals such as zircons. We analyse the quartz or feldspar minerals in sand deposits. When these quartz or feldspar minerals are exposed to the ionising radiation emitted by the radioactive isotopes in zircons, electrons within the crystals migrate and become trapped in their crystal structure.
The number of trapped electrons depends on the total amount of radiation that the mineral has been exposed to. If we assume that the radiation dose rate of the sediment has remained constant over time, then if we measure that dose rate, we can calculate the sample age. Photograph used with permission of Geoff Duller.
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The impetus behind this study is to understand the sedimentological dynamics of very young fluvial systems in the Amazon River catchment and relate these to land use change and modern analogue studies of tidal rhythmites in the geologic record. Many of these features have an appearance of freshly deposited pristine sand, and these observations and information from anecdotal evidence and LandSat imagery suggest an apparent decadal stability.
Signals from medium-sized aliquots 5 mm diameter exhibit very high specific luminescence sensitivity, have excellent dose recovery and recycling, essentially independent of preheat, and show minimal heat transfer even at the highest preheats. Significant recuperation is observed for samples from two of the study sites and, in these instances, either the acceptance threshold was increased or growth curves were forced through the origin; recuperation is considered most likely to be a measurement artefact given the very small size of natural signals.
Despite the use of medium-sized aliquots to ensure the recovery of very dim natural OSL signals, these results demonstrate the potential of OSL for studying very young active fluvial processes in these settings.
Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) Dating of Two Burned Clovis Wyandotte Chert Lithic Specimens from.
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.
Luminescence and ESR Dating
We report the abandonment age of the Jeongdongjin JDJ coastal terrace that lies at 65 m a. The reliability of applied indirect age constraints on the sediments by amino-acid racemization and tephra chronology is debated. We present the first application of cosmogenic surface exposure dating to constrain the age of the old terrace in Korea. We dated four samples from the paleo shore platform surface using cosmogenic 10 Be surface exposure dating techniques.
The analyses yielded exposure ages ranging from to kyr and likely correspond to the penultimate interglacial period MIS 7.
Initial quartz optically stimulated luminescence (OSL) dating feasibility studies have concentrated on spit and bar deposits in the Rio Tapajós.
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 Open Geography Journal
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.
Ongoing work is examining whether unfired clay bricks from various sites can be dated accurately. OSL techniques are being applied to date sediment sequences in stratigraphic contexts associated with irrigation systems.
PANGAEA, , In: Han, Z (): OSL dating of beach ridges of Dali Lake and reconstruction of hydrological parameters.
In West Africa, preservation conditions of the sediments have only rarely been favorable to the recording of long sedimentary and archaeological sequences. Most of the artifacts are surface finds, making it difficult, if not impossible, to place them in chronological context, whether it be relative or absolute. However, in the Dogon Country, deep sedimentary deposits have been preserved in several sectors, trapping abundant evidence of human occupations during the Paleolithic and making it possible to study their chronology.
While the range of applicable dating methods is limited, given the exclusive preservation of mineral materials, with the exception of Holocene charcoals, conditions are favorable for dating by optically stimulated luminescence OSL : the sediments are mainly formed of quartz, which, moreover, has a particularly strong luminescence signal in this region.
The radioactive elements of the uranium, thorium and potassium families are naturally present in very low amounts in all sediments. Radioactive decay is accompanied by energy release, some of which is absorbed by nearby minerals. When these are subjected to light stimulus, the accumulated energy in the crystalline networks is released, causing a light emission: this is optically stimulated luminescence or OSL. When sediment is exposed to natural light prior to deposition, the OSL acquired over geological time is removed.