Meas. Reporter genes are valuable tools for studying gene expression, serving as surrogates for genes involved in various signaling pathways and disease conditions. Athropol. The tester then inspects the dye in darkness with an ultraviolet lamp, which makes the remaining dye shine and show up, so revealing the cracks. Radiat. Proc. Gurin, G., Mercier, N. & Adamiec, G. Dose-rate conversion factors: update. Sci. 30, 472478 (2015). A. J. Archaeol. Balescu, S. & Lamothe, M. Comparison of TL and IRSL age estimates of feldspar coarse grains from waterlain sediments. Sect. Meas. 362, 3441 (2015). The rate of energy absorption from ionizing radiation during burial (grays per thousand years ago). Int. 245, 673684 (2006). & Heiniger, L. Uniform erosion rates and relief amplitude during glacial cycles in the Southern Alps of New Zealand, as revealed from OSL-thermochronology. Nathan, R., Puthusserry, T., Jain, M. & Murray, A. S. Environmental dose rate heterogeneity due to beta microdosimetry and its implications for luminescence dating: Monte Carlo modelling and experimental validation. 39, 309318 (2005). 162, 88110 (2017). Palaeogeogr. Quat. Radiat. Jain, M., Murray, A. S. & Btter-Jensen, L. Optically stimulated luminescence dating: how significant is incomplete light exposure in fluvial environments? Porat, N., Levi, T. & Weinberger, R. Possible resetting of quartz OSL signals during earthquakes evidence from late Pleistocene injection dikes, Dead Sea basin, Israel. Thermoluminescence can be used to date materials containing crystalline minerals to a specific heating event. (which our eyes can see) and ultraviolet light (which we can't see). Kocurek, G. et al. Macrophages are a type of white blood cell that plays a role in detecting and destroying, ELISA methods have become widely used across various fields of biology, from healthcare and food safety to cancer research and vaccine development. Quat. Quat. Please do NOT copy our articles onto blogs and other websites. What is Luminescence Dating? 500, 2031 (2019). 7, 373380 (1988). 1, 305312 (2006). Evolut. & Thewalt, M. L. W. Optical dating of sediments. Ballarini, M., Wallinga, J., Wintle, A. G. & Bos, A. J. J. 30, 134140 (2015). Haile, J. et al. Radiat. 35,000years ago. Heier-Nielsen, S. et al. Rev. Lvborg, L. & Kirkegaard, P. Response of 33 NaI(Tl) detectors to terrestrial gamma radiation. 9, 983 (2018). Old-style, cathode-ray television sets (and Thermoluminescence Dating Like luminous watches, the phosphor chemicals are still excited enough to give off light for some time after they've been stimulated. Landslides 15, 19751989 (2018). 297, 183189 (2010). Radiat. Pawley, S. M., Bailey, R. M., Rose, J., Moorlock, B. S. P. & Hamblin, R. J. O. Hu, G., Yi, C.-L., Zhang, J.-F., Liu, J.-H. & Jiang, T. Luminescence dating of glacial deposits near the eastern Himalayan syntaxis using different grain-size fractions. Quat. Radiocarbon dating of shells and foraminifera from the Skagen Core, Denmark: evidence of reworking. Andrew Murray. Radiat. creatures. Earliest occupation of the Central Aegean (Naxos), Greece: implications for hominin and Homo sapiens behavior and dispersals. 2023 Molecular Devices, LLC. In a porous body (of sediment), the part lying between the ground surface and the water table. Sci. Radiat. Kang, S. et al. more about how atoms make light in the feature box in our article on 23, 593600 (1994). Radiat. 75, 155175 (2006). Estimation of possible maximum earthquake magnitudes of Quaternary faults in the southern Korean Peninsula. A single aliquot procedure for determining the equivalent dose De, based on resetting the luminescence signal to zero between each measurement of luminescence, whether resulting from natural or laboratory doses. 120, 96103 (2018). It's an example of what's called The SAR protocol offers significant advantages over the earlier multiple aliquot approach which only produced one normalised natural value (Ln) from the use of 24-48 aliquots per sample, and was then used to extrapolate a De value from the dose response curve. Meas. 15, 751760 (1996). Geochronol. B. When the promoter is activated, the reporter gene is expressed and its levels can be measured. Timar-Gabor, A. et al. Pract. Pietsch, T. J., Olley, J. M. & Nanson, G. C. Fluvial transport as a natural luminescence sensitiser of quartz. Earth Surf. Geochronometria 45, 5667 (2019). Radiat. Palaeogeogr. Sci. Palaeoecol. Similarly, surprisingly little work has been done to apply luminescence procedures to date lacustrine deposits, in spite of the rapid development, the widespread uptake, and the improved accuracy and precision of luminescence dating when applied to a wide variety of other depositional settings. Photo by Radiat. Phys. Often used more informally to describe gradational boundaries. In archaeology the OSL method is used to date pottery and other heated materials (e.g., bricks, stones, earth) or sediments related to archaeological finds. the emission of a characteristic colour of light) when stimulated. Armitage, S. J. Photo by 5, 299305 (2010). Meas. Geochronol. Can. Adv. Radiat. Quat. Quat. Quat. J. Hum. Earth Planet. Geochronol. Heydari, M. & Gurin, G. OSL signal saturation and dose rate variability: investigating the behaviour of different statistical models. Meas. 97, 184214 (2009). Geochronol. Mller, P. & Murray, A. S. Drumlinised glaciofluvial and glaciolacustrine sediments on the Smland peneplain, south Sweden new information on the growth and decay history of the Fennoscandian ice sheets during MIS 3. Sci. The flexibility of luminescence is a key complement to other chronometers such as radiocarbon or . Geochronol. Nucl. Peng, J., Dong, Z., Han, F., Long, H. & Liu, X. R package numOSL: numeric routines for optically stimulated luminescence dating. We use a range of sampling techniques in the field. Proc. Meas. It is in contrast to light emitted from incandescent bodies, such as burning wood or coal, molten iron, and wire heated by an electric current. Olley, J. M., Caitcheon, G. G. & Roberts, R. G. The origin of dose distributions in fluvial sediments, and the prospect of dating single grains from fluvial deposits using optically stimulated luminescence. Forensics 21, 291309 (2020). & Arnold, L. J. 80, 111136 (2007). Sci. 234, 106262 (2020). Quat. Rev. Quat. 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. . & Pinder, R. C. Testing the applicability of optically stimulated luminescence dating to Ocean Drilling Program cores. Cultural innovation and megafauna interaction in the early settlement of arid Australia. 17, 197206 (1990). Optically stimulated luminescence (OSL) signals from quartz can be used to determine when sedimentary archives were deposited. J.) The SAR approach provides multiple Des and also allows for the explicit testing of partial bleaching. is funded by the National Natural Science Foundation of China (NSFC41671008). The count rate from a photon detector completely obscured from light (per second). Rev. Geochronol. a vacuum fluorescent display. J. Phys. Guralnik, B. et al. Theory stating that the sum of independent random variables tends towards a normal distribution, even when the original variables themselves are not normally distributed. In this chapter, the application of luminescence techniques in dating geological and archaeological events is examined. 42, 12651272 (2007). Rufer, D. & Preusser, F. Potential of autoradiography to detect spatially resolved radiation patterns in the context of trapped charge dating. 26, 26172630 (2007). with many other kinds of energy. Radiat. Zhang, X. L. et al. Luminescence dating of buried cobble surfaces from sandy beach ridges: a case study from Denmark. Department of Geoscience, Aarhus University, Aarhus, Denmark, School of Physical Sciences, Environment Institute, Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, South Australia, Australia, Department of Physics, Technical University of Denmark, Roskilde, Denmark, Jan-Pieter Buylaert&Kristina J. Thomsen, IRAMAT-CRP2A, UMR 5060 CNRS Universit Bordeaux Montaigne, Maison de larchologie, Pessac, France, Universit Rennes, CNRS, Gosciences Rennes, UMR 6118, Rennes, France, State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, China, Xinjiang Pamir Intracontinental Subduction National Field Observation and Research Station, Institute of Geology, China Earthquake Administration, Beijing, China, AMOPH Division, Physical Research Laboratory, Navarangpura, Ahmedabad, India, Department of Geography and Planning, University of Liverpool, Liverpool, UK, You can also search for this author in Herman, F., Rhodes, E. J., Braun, J. Alternative chronologies for Late Quaternary (Last Interglacial-Holocene) deep sea sediments via optical dating of silt-sized quartz. & Roberts, R. G. Single-grain OSL dating of glaciofluvial quartz constrains Reid glaciation in NW Canada to MIS 6. Sugisaki, S. et al. Benea, V. et al. Mar. Curr. Rad. 27, 611624 (1997). Variations in luminescence properties of quartz and feldspar from modern fluvial sediments in three rivers. of crime. Sohbati, R., Murray, A. S., Jain, M., Buylaert, J. P. & Thomsen, K. J. 29, 561572 (1998). Sci. Absolute dating of past seismic events using the optically stimulated luminescence (OSL) technique on fault gouge material a case study of the Nojima Fault Zone, SW Japan. Ankjrgaard, C. & Jain, M. Optically stimulated phosphorescence in quartz over the millisecond to second time scale: insights into the role of shallow traps in delaying luminescent recombination. Geochronometria 28, 916 (2007). The energy absorbed per unit mass from ionizing radiation: 1Gy=1Jkg1. J.-P.B. With this bleaching effect removed, the influence, albeit often weak, of naturally-occurring radioactive elements (primarily potassium-40, uranium and thorium) within the sediment together with incoming cosmic rays results in the accumulation of a signal within individual mineral grains (most commonly quartz and feldspars). Thus . The material covering some geological feature of interest. Sci. Human Evol. Photo: How invisible security inks and paints work, compared to normal inks and paints. A constant used to describe the curvature of the luminescence response to the dose D, usually in an expression of the form Y=A[1exp(D/Dc)] where A is a constant describing the upper limit to Y (grays). & Ito, K. OSL dating of the AD 869 Jogan tsunami deposit, northeastern Japan. Loess correlations between myth and reality. 39, 4761 (2005). J. Asian Earth Sci. Proc. 43, 752757 (2008). et al. Chen, Y. W., Chen, Y.-G., Murray, A. S., Liu, T. K. & Lai, T. C. Luminescence dating of neotectonic activity on the southwestern coastal plain, Taiwan. Thomas, P. J., Murray, A. S., Kjr, K. H., Funder, S. & Larsen, E. Optically stimulated luminescence (OSL) dating of glacial sediments from Arctic Russia depositional bleaching and methodological aspects. Sci. (see Figure 1). UV lights are used to luminescence, emission of light by certain materials when they are relatively cool. Int. Nature 289, 479480 (1981). Geochronol. Quat. Radiat. What is Luminescence, Luminometer, Bioluminescence | Molecular Devices Geochronol. Archaeometry 41, 339364 (1999). 30, 363368 (2015). 23, 12291271 (2004). Meas. Radiat. An animal burrow that has been back-filled with material from overlying sediments. Sci. this are incandescent and make light by making heat. Change 168, 114 (2018). Science 367, 1443 (2020). 30, 207217 (1999). Radiat. 40, 22172226 (2013). Strictly speaking, that means the Sun (top) is luminous but the Moon (bottom) is not. and K.J.T. 13, 1825 (2012). 49, 223229 (2019). But there are many other ways we use luminescence too. When a geological sediment is buried, the effects of the incoming solar radiation are removed. 13, 525528 (1994). 12071211, 22 (2003). 92, 464472 (2011). Radiat. 20, 14751560 (2001). 8, 2332 (2012). Radiat. High resolution optically stimulated luminescence dating of a sediment core from the southwestern Sea of Okhotsk. Quat. In the context of using luminescence for dating, the luminescence signal arises from the release of energy stored from prior exposure to ionizing radiation such as alpha, beta, or gamma radiation. Extraordinary floods of 4100-4000 a BP recorded at the Late Neolithic ruins in the Jinghe River gorges, middle reach of the Yellow River, China. Fuchs, M. & Owen, L. A. Luminescence dating of glacial and associated sediments: review, recommendations and future directions. Meas. To remove this element a preheat is administered, which in turn may increase the sensitivity of the sample to further irradiation. Quat. Geomorphology 370, 107371 (2020). Murray, A. S., Roberts, R. G. & Wintle, A. G. Equivalent dose measurement using a single aliquot of quartz. Relic permafrost structures in the Gobi of Mongolia: age and significance. PLoS ONE 8, e69280 (2013). Singhvi, A. K. & Porat, N. Impact of luminescence dating on geomorphological and palaeoclimate research in drylands. Singh, A. et al. Meas. Quat. Torabi, M., Fattahi, M., Amini, H., Ghassemi, M. R. & Karimi, N. OSL dating of landslide-dammed-lake deposits in the North of Tehran, Iran: 958 Ray-Taleghan/Ruyan earthquake. A mound complex in Louisiana at 54005000years before present. Luciferases are the most, Reporter gene assays are important tools for studying gene expression associated with the activation of cellular pathways. On the dose-rate estimate of carbonate-rich sediments for trapped charge dating. cence dating stands a much better chance of providing this today than it did 30 years ago. How does thermoluminescence dating work 246, 106553 (2020). Rev. 5, 329335 (2010). Yang, H. L., Chen, J., Thompson, J. 27, 171184 (1997). A fossil soil (that is, one no longer forming); usually found buried within a sequence of sedimentary units. Chapot, M. S., Sohbati, R., Murray, A. S., Pederson, J. L. & Rittenour, T. M. Constraining the age of rock art by dating a rockfall event using sediment and rock-surface luminescence dating techniques. Shen, H., Yu, L., Zhang, H., Zhao, T. M. & Lai, Z. OSL and radiocarbon dating of flood deposits and its paleoclimatic and archaeological implications in the Yihe River Basin, East China. 15, 215220 (2018). GSA Bulletin 131, 20942109 (2019). D Appl. Buylaert, J.-P. et al. Preusser, F., Rufer, D. & Schreurs, G. Direct dating of Quaternary phreatic maar eruptions. This work presents a review of the benefits and disadvantages of dose measurements using single grains. Murray, A. S. Developments in optically transferred luminescence and photo-transferred thermoluminescence dating: application to a 2000-year sequence of flood deposits. High resolution OSL dating back to MIS 5e in the central Sea of Okhotsk. Olley, J. M. et al. Radiocarbon dating works by comparing the three different isotopes of carbon. Wolfe, S., Murton, J., Bateman, M. & Barlow, J. Oriented-lake development in the context of late Quaternary landscape evolution, McKinley Bay Coastal Plain, western Arctic Canada. Get the most important science stories of the day, free in your inbox. Optical dating of relict sand wedges and composite-wedge pseudomorphs in Flanders, Belgium. electricity (electrical energy) into light and shines it toward us. Choi, J. H., Murray, A. S., Cheong, C. S., Hong, D. G. & Chang, H. W. The resolution of stratigraphic inconsistency in the luminescence ages of marine terrace sediments from Korea. Xu, Z. et al. Now, if the ink is invisible and shows up only in invisible Radiat. Westgate, J. J. Quat Sci. Sci. Luminescence, fluorescence, and phosphorescence - Explain that Stuff Radiat. Rev. Aitken, M. J. A dating technique based on the decay of 40K to 40Ar. This article depicts the different forms of luminescences and goes into detail in the case of fluorescence. }, Photo: Bioluminescence (an eerie blue glow produced by ocean creatures) in the East China Sea, witnessed from the side of a ship. 51, 255273 (2006). Quat. Radiat. Palaeogeogr. A. http://www.britice-chrono.group.shef.ac.uk/, INQUA Dunes Atlas: It is this signal that is the key to luminescence dating techniques. Quat. Anc. Anc. The best intruder alarm in the world can't always keep thieves out Sci. 4, 115135 (2012). Quat. Light absorption and photoluminescence (PL) spectroscopy Demuro, M., Arnold, L. J., Pars, J. M. & Sala, R. Extended-range luminescence chronologies suggest potentially complex bone accumulation histories at the Early-to-Middle Pleistocene palaeontological site of Huscar-1 (Guadix-Baza basin, Spain). & Arsuaga, J. L. Single-grain OSL dating of the Middle Palaeolithic site of Galera de las Estatuas, Atapuerca (Burgos, Spain). Given an estimate of the rate of received ionizing radiation (the dose rate, or D), and knowing the total accumulated dose (the palaeodose; designated DE) it is possible to derive an age since burial. Quat. Permanent human occupation of the central Tibetan Plateau in the Early Holocene. Quat. It's made from materials such as 3M Scotchlite, which uses tiny reflective beads to throw back more light. Luminous is quite a vague word really. New ages for human occupation and climate change at Lake Mungo, Australia. This is useful for ceramics, as it determines the date of firing, as well as for lava, or even sediments that were exposed to substantial sunlight. 43, 195501 (2010). All rights reserved. Isotopes of a particular element have the same number of protons in their nucleus, but different numbers of neutrons . Gliganic, L. A., Meyer, M. C., Sohbati, R., Jain, M. & Barret, S. OSL surface exposure dating of a lithic quarry in Tibet: laboratory validation and application. Rowan, A. V. et al. 10, 250256 (2012). Despite this, through the careful choice and collection of samples, as well as stringent preparation and analytical methods, it is possible to produce ages with an accuracy of between 5 and 12%. Tsakalos, E. et al. Nathan, R. P. & Mauz, B. Quat. Geochronol. Quat. Boreas 43, 121 (2014). What other types of luminescence are there? Meas. J. Quat. Radiat. Sci. But for other applications like BRET, a luminescence plate reader can be equipped with filters or monochromators that allow the selection of specific wavelengths in order to measure binding or other biomolecular events. A hydraulic drive with a range of different heads can be used in conjunction with hand auguring to punch through calcrete or silcrete layers within the landform of interest. Guibert, P., Lahaye, C. & Bechtel, F. The importance of U-series disequilibrium of sediments in luminescence dating: a case study at the Roc de Marsal cave (Dordogne, France). Lai, Z. P., Brckner, H., Zller, L. & Fllinga, A. 27, 5265 (2015). Geochronol. While they play an important role in generating data from a, Many microplate readers and spectrophotometers use a photomultiplier tube (PMT) to detect fluorescence and luminescence signals. 22, 11771183 (2003). 4) In UV light, the invisible ink reflects visible lightso it shows up red or another color. Tamura, T. et al. 30, 264269 (2015). Gurin, G. & Mercier, N. Determining gamma dose rates by field gamma spectroscopy in sedimentary media: results of Monte Carlo simulations. 36, 651660 (2010). Sometimes phosphorescence lasts for a few seconds Btter-Jensen, L. et al. Dosimetry 141, 2735 (2010). & Roberts, R. G. Advances in optically stimulated luminescence dating of individual grains of quartz from archeological deposits. USA 111, 1298612991 (2014). Rev. Equivalent dose estimation from a single aliquot of polymineral fine-grains. Quat. Philippe, A., Gurin, G. & Kreutzer, S. BayLum an R package for Bayesian analysis of OSL ages: an introduction. Srivastava, P., Singh, I. Int. Geochronol. Quartz as a natural luminescence dosimeter. Radiat. Hamm, G. et al. Full copyright notice and terms of use. Luminescence dating encompasses a range of methods that seek to determine when mineral grains were last exposed to sunlight or heat. Geochronol. over it, the markings (maybe your name or zip code) show up, and they Kristensen, J. Firstly, the natural signal (Ln) present in the sample is measured, followed by a series of rising known radiation doses from which a dose response curve can be constructed (Figure 4). Lancaster, N. et al. 44, 417422 (2009). Uncertainties and minimum reporting are discussed together with methodological limitations, particularly when applied to young and old sediments. See more. Quat. Heimsath, A. M., Chappell, J., Spooner, N. A. You've probably noticed that it Scientists almost have an entire A-Z Res. Meas. to normal, in just a few nanoseconds, they Geol. Acta 60, 565576 (1996). Quat. Process. In eukaryotes, these molecules are mainly created during aerobic respiration and can cause problems,, Mycoplasma, the smallest and simplest of the prokaryotes, are common contaminants of cell cultures. Petraglia, M. et al. 30, 200206 (2015). & Jain, M. The dose dependency of the over-dispersion of quartz OSL single grain dose distributions. 2) In UV light, ordinary inks tend to turn black. 89, 7782 (1993). Walter, R. C. in Chronometric Dating in Archaeology (eds Taylor, R. E. A. Quat. Late Middle Pleistocene Levallois stone-tool technology in southwest China. Radiat. Soc. Luminescence dating is possible because this radiation increases the amount of energy stored inside certain minerals, almost like a rechargeable battery. US Department of Energy/National Renewable Energy Laboratory (DOE/NREL). Geochronol. 77, 305316 (2012). Meas. Corals and 47, 688695 (2012). Meas. Sci. Rittenour, T. Luminescence dating of fluvial deposits: applications to geomorphic, palaeoseismic and archaeological research. 5, 306310 (2010). 91, 263269 (2012). When we talk about "luminous" watches and paint, Hydrological transformation coincided with megafaunal extinction in central Australia. & Zhou, L. P. A new luminescence chronology for the Mangshan loesspalaeosol sequence on the southern bank of the Yellow River in Henan, central China. Quat. 49, 138145 (2019). 3860 N First Street San Jose, CA 95134. Chapot, M., Roberts, H. M., Duller, G. A. Existence of a common growth curve for silt-sized quartz OSL of loess from different continents. Int. 433, 102115 (2017). New ages for the last Australian megafauna: continent-wide extinction about 46,000years ago. This stored radiation dose can be evicted with stimulation and released as luminescence. you find scienceeven lurking in your laundry! Noller, J. S., Sowers, J. M., Lettis, W. R. Quaternary Geochronology: Methods and Applications (American Geophysical Union, 2013). Murton, J. Meas. Depth dependent soil mixing persists across climatic zone. Quat. Quat. Gurin, G. & Mercier, N. Field gamma spectrometry, Monte Carlo simulations and potential of non-invasive measurements. SpectraNet is an intuitive, simple-to-use, self-service customer portal providing a new level of experience available 24/7. Instrum. Liu, Z., Zhao, H., Wang, C. M. & Li, S. H. Estimation of paleo-firing temperatures using luminescence signals for the volcanic lava baked layer in Datong, China. Single-grain TT-OSL bleaching characteristics: Insights from modern analogues and OSL dating comparisons. Geology 39, 11351138 (2011). Rev. Zimmerman, D. W. Thermoluminescent dating using fine grains from pottery. 31, 7796 (2016). Meas. 2023 Molecular Devices, LLC. Godfrey-Smith, D. I. Sci. What is Thermoluminescence Dating and How Does It Work? Meas. Cracks formed in frozen ground and then filled with sand; this preserves them in the sedimentary record. Geochronol. ); Experimentation (A.M., L.J.A., J.-P.B., G.G., J.Q., A.K.S., R.S. 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. Res. their loot, how can they ever return it to its rightful owners? How does Luminescence work? Radiat. Singarayer, J. S. & Bailey, R. M. Component-resolved bleaching spectra of quartz optically stimulated luminescence: preliminary results and implications for dating. Minimizing feldspar OSL contamination in quartz UV-OSL using pulsed blue stimulation. Cosmogenic nuclide and optically stimulated luminescence tracers. Bronk Ramsey, C. Radiocarbon dating: revolutions in understanding. Brown, N. D. Which geomorphic process can be informed by luminescence measurements? Method. 362, 2333 (2015). takes a bit of time to "charge up" a luminous watch with energy Bowler, J. M. et al. Google Scholar. Copying or otherwise using registered works without permission, removing this or other copyright notices, and/or infringing related rights could make you liable to severe civil or criminal penalties. Text copyright Chris Woodford 2008, 2020. Geochronol. Quat. 58, 101074 (2020). Geochronol. Demuro, M., Froese, D. G., Arnold, L. J. & Jain, M. Review of optically stimulated luminescence (OSL) instrumental developments for retrospective dosimetry. Holocene 26, 532548 (2015). OSL-thermochronometry using bedrock quartz: a note of caution. This is obtained from the formula: This accumulated signal results in luminescence (i.e. Commun. Chemical and radiometric assessment of the surrounding sediment, through in-situ gamma spectrometry or laboratory high-resolution gamma spectrometry, identifies the proportions of each element together with the contribution from the alpha, beta and gamma components. Sci. Sci. Gliganic, L. A., Jacobs, Z. Geochronol. The Application of Luminescence Dating in American Archaeology Lett. Kreutzer, S. et al. what we really mean is phosphorescence, which is White microplates are usually recommended for luminescence as they reflect light and maximize the signal. Li, G. et al. J. Geosci. Kortekaas, M., Murray, A. S., Sandgren, P. & Bjrck, S. OSL chronology for a sediment core from the southern Baltic Sea: a continuous sedimentation record since deglaciation.