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”. The trapped charge accumulates over time at a rate determined by the amount of background radiation at the location where the sample was buried.
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.
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.
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. An important facet of the development of a geochronological technique is the investigation of potential age range. Much recent work in the luminescence field has focused on maximum achievable ages using high-temperature post-infrared infrared pIRIR signals from feldspars [ 1 , 2 ].
In contrast for quartz optically stimulated luminescence OSL , the more efficient signal resetting coupled with environments where grain reworking is evident make it well suited to assessment of minimum achievable age. Notable examples are studies of young fluvial deposits [ 3 , 4 , 5 , 6 ] and dunes [ 7 , 8 , 9 , 10 , 11 ].
Optically Stimulated Luminescence
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.
Single-grain OSL dating of glaciofluvial quartz constrains Reid glaciation in NW Canada to MIS 6 – Volume 77 Issue 2 – Martina Demuro, Duane G. Froese, Lee.
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. Within the School of Geography and the Environment, the OLD Laboratory provides support particularly for the Landscape Dynamics research cluster, with a specific focus on low latitude environment and climate change, geoarchaeology and geomorphology.
In addition our researchers continuously engage in efforts to improve and develop the methodology and to further advance our knowledge on the fundamental physical mechanisms underlying the dating method. The OLD Laboratory also provides a commercial luminescence dating service and works closely with clients in industry, archaeological organizations, environmental institutes and other academic groups. For commercial enquiries please contact Dr Szilvia Bajkan in the first instance clearly stating the following information:.
Depositional context of material e. Region from which samples are derived. If known, approximate estimate of age e. Timeframe of project i.
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.
Initial quartz optically stimulated luminescence (OSL) dating feasibility studies have concentrated on spit and bar deposits in the Rio Tapajós.
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. Sedimentation processes on Mars are completely unexplored. In addition, fluid phases may have contributed significantly to erosion and transport processes to form the Martian landscape. Dating of buried grains in sedimentary layers would give a crucial contribution to the understanding of surface forming processes and is essential for any further exploration of planet Mars.
It is therefore essential to develop a method, which can determine the chronology of sedimentary deposits. Such a technique must be incorporated into an instrument requiring low resources mass, power, volume and placed onto the surface of Mars.
Luminescence Dating: Applications in Earth Sciences and Archaeology
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. The results indicate spatio-temporal variations in the rate of surface uplift along the east coast of Korea during the late Quaternary.
The paper then explains how OSL dating is applied to obtain a depositional age, through the field and laboratory procedures employed. These procedures are.
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. In the absence of suitable organic samples for C dating, these systems are very difficult to date. New approaches are being applied to the dating of post-Roman irrigation systems in Spain to establish when they were created and used. Also, as part of a major investigation supported by the European Research Centre and led by Prof.
Sauer at the University of Edinburgh, a PhD project has started to investigate the application of OSL and geomorphological techniques to establish the chronology of irrigation systems and settlement sites associated with the demographic growth at the frontiers of the Sasanian Empire. The availability of chronologies for aeolian horizons obtained using OSL provides a valuable tool in the study of the evolution of coastal landscape and how past coastal communities responded to climate change.
The OSL dating of sands and palaeosol horizons, supported by geomorphological analysis, has identified critical stages in the development of the landscape on Herm on which megalithic monuments were constructed during the Neolithic period.
Optically stimulated Luminescence dating of quartz
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.
is an acronym for Optically-Stimulated Luminescence. Optically-Stimulated Luminescence is a late Quaternary.
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.
Optically Stimulated Luminescence Dating Lab
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. Dividing the equivalent dose by the dose rate yields time.
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. OSL dating of fine-grained fluvial deposits may have an underutilised potential for establishing an accurate chronology of mud-dominated floodplain evolution. The Mekong River is one of the largest river systems in the world, with a large sediment discharge comparable to other larger Asian river systems such as Yellow and Ganges—Brahmaputra rivers.